Storage and retrieval system

ABSTRACT

A storage and retrieval system including a vertical array of storage levels, each storage level having, picking aisles, storage locations, disposed within the picking aisles, and at least one transfer deck providing access to the picking aisles, a multilevel vertical conveyor system configured to transport the uncontained case units to and from the vertical array of storage levels, each storage level being configured to receive uncontained case units from the multilevel vertical conveyor system, at least one autonomous transport located on each storage level for transporting the uncontained case units between respective storage locations and the multilevel vertical conveyor system, and a controller configured to create a primary access path through the transfer decks and picking aisles to a predetermined one of the storage locations and at least one secondary access path to the predetermined one of the storage locations when the primary path is impassible.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/168,349 filed on Apr. 10, 2009, the disclosure ofwhich is incorporated herein by reference in its entirety.

This application is related to U.S. patent application Ser. No.12/757,381, entitled “STORAGE AND RETRIEVAL SYSTEM,” filed on Apr. 9,2010; U.S. patent application Ser. No. 12/757,337, entitled “CONTROLSYSTEM FOR STORAGE AND RETRIEVAL SYSTEMS,” filed on Apr. 9, 2010; U.S.patent application Ser. No. 12/757,354, entitled “LIFT INTERFACE FORSTORAGE AND RETRIEVAL SYSTEMS,” filed on Apr. 9, 2010; and U.S. patentapplication Ser. No. 12/757,312, entitled “AUTONOMOUS TRANSPORTS FORSTORAGE AND RETRIEVAL SYSTEMS,” filed on Apr. 9, 2010, the disclosuresof which are incorporated by reference herein in their entireties.

BACKGROUND

1. Field

The exemplary embodiments generally relate to material handling systemsand, more particularly, to automated storage and retrieval systems.

2. Brief Description of Related Developments

Warehouses for storing case units may generally comprise a series ofstorage racks that are accessible by transport devices such as, forexample, fork lifts, carts and elevators that are movable within aislesbetween or along the storage racks or by other lifting and transportingdevices. These transport devices may be automated or manually driven.Generally the case units stored on the storage racks are contained incarriers, for example storage containers such as trays, totes orshipping cases, or on pallets. Generally, incoming pallets to thewarehouse (such as from manufacturers) contain shipping containers (e.g.cases) of the same type of goods. Outgoing pallets leaving thewarehouse, for example, to retailers have increasingly been made of whatmay be referred to as mixed pallets. As may be realized, such mixedpallets are made of shipping containers (e.g. totes or cases such ascartons, etc.) containing different types of goods. For example, onecase on the mixed pallet may hold grocery products (soup can, soda cans,etc.) and another case on the same pallet may hold cosmetic or householdcleaning or electronic products. Indeed some cases may hold differenttypes of products within a single case. Conventional warehousingsystems, including conventional automated warehousing systems do notlend themselves to efficient generation of mixed goods pallets. Inaddition, storing case units in, for example carriers or on palletsgenerally does not allow for the retrieval of individual case unitswithin those carriers or pallets without transporting the carriers orpallets to a workstation for manual or automated removal of theindividual case units.

It would be advantageous to have a storage and retrieval system forefficiently storing and retrieving individual case units withoutcontaining those case units in a carrier or on a pallet.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and other features of the disclosed embodimentsare explained in the following description, taken in connection with theaccompanying drawings, wherein:

FIG. 1 schematically illustrates an exemplary storage and retrievalsystem in accordance with an exemplary embodiment;

FIGS. 2A, 2B, 2C, 2D, 3A and 3B illustrate schematic views of a conveyorsystem in accordance with an exemplary embodiment;

FIG. 4 illustrates a schematic view of a conveyor shelf in accordancewith an exemplary embodiment;

FIG. 5 schematically illustrates a conveyor system in accordance with anexemplary embodiment;

FIGS. 6A-6D schematically illustrate a transfer station in accordancewith an exemplary embodiment.

FIGS. 7 and 8A-8C illustrate a transport robot in accordance with anexemplary embodiment;

FIGS. 9A and 9B illustrate partial schematic views of the transportrobot of FIGS. 7, 8A and 8B in accordance with an exemplary embodiment;

FIG. 9C illustrates a schematic view of a transport robot in accordancewith an exemplary embodiment;

FIGS. 10A-10C and 11A-11D illustrate a portion of a transfer arm of thetransport robot of FIGS. 7, 8A and 8B in accordance with an exemplaryembodiment;

FIG. 12 schematically illustrates a control system of the transportrobot of FIGS. 2, 3A and 3B in accordance with an exemplary embodiment;

FIG. 13-15 illustrate schematic plan views of storage and retrievalsystems having different configurations in accordance with the exemplaryembodiments;

FIG. 16 illustrates a structural portion of a storage and retrievalsystem in accordance with an exemplary embodiment;

FIGS. 17A and 17B illustrate storage shelves in accordance with anexemplary embodiment;

FIGS. 18, 19A and 19B schematically illustrate exemplary operationalpaths of a transport robot in accordance with the exemplary embodiments;

FIG. 20A illustrates a conventional organization of item storage in astorage bay;

FIG. 20B illustrates an organization of case units in a storage bay inaccordance with an exemplary embodiment;

FIG. 20C illustrates a comparison of unused storage space between theitem storage of FIG. 20A and the item storage of FIG. 20B;

FIG. 21 is a schematic illustration of a method in accordance with anexemplary embodiment; and

FIGS. 22 and 23 are flow diagrams of exemplary methods in accordancewith the exemplary embodiments.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT(S)

FIG. 1 generally schematically illustrates a storage and retrievalsystem 100 in accordance with an exemplary embodiment. Although theembodiments disclosed will be described with reference to theembodiments shown in the drawings, it should be understood that theembodiments disclosed can be embodied in many alternate forms. Inaddition, any suitable size, shape or type of elements or materialscould be used.

In accordance with one exemplary embodiment the storage and retrievalsystem 100 may operate in a retail distribution center or warehouse to,for example, fulfill orders received from retail stores for case units(where case units as used herein means case units not stored in trays,on totes or on pallets, e.g. uncontained). It is noted that the caseunits may include cases of case units (e.g. case of soup cans, boxes ofcereal, etc.) or individual case units that are adapted to be taken offof or placed on a pallet. In accordance with the exemplary embodiments,shipping cases or case units (e.g. cartons, barrels, boxes, crates,jugs, or any other suitable device for holding case units) may havevariable sizes and may be used to hold case units in shipping and may beconfigured so they are capable of being palletized for shipping. It isnoted that when, for example, bundles or pallets of case units arrive atthe storage and retrieval system the content of each pallet may beuniform (e.g. each pallet holds a predetermined number of the sameitem—one pallet holds soup and another pallet holds cereal) and aspallets leave the storage and retrieval system the pallets may containany suitable number and combination of different case units (e.g. eachpallet may hold different types of case units—a pallet holds acombination of soup and cereal). In alternate embodiments the storageand retrieval system described herein may be applied to any environmentin which case units are stored and retrieved.

The storage and retrieval system 100 may be configured for installationin, for example, existing warehouse structures or adapted to newwarehouse structures. In one exemplary embodiment, the storage andretrieval system may include in-feed and out-feed transfer stations 170,160, multilevel vertical conveyors 150A, 150B, a storage structure 130,and a number of autonomous vehicular transport robots 110 (referred toherein as “bots”). In alternate embodiments the storage and retrievalsystem may also include robot or bot transfer stations 140 (FIGS. 6A-6D)that may provide an interface between the bots 110 and the multilevelvertical conveyors 150A, 150B as will be described below. The storagestructure 130 may include multiple levels of storage rack modules whereeach level includes respective picking aisles 130A, and transfer decks130B for transferring case units between any of the storage areas of thestorage structure 130 and any shelf of any multilevel vertical conveyor150A, 150B. The picking aisles 130A, and transfer decks 130B also allowthe bots to place case units into picking stock and to retrieve orderedcase units. In alternate embodiments, each level may also includerespective bot transfer stations 140. The bots 110 may be configured toplace case units, such as the above described retail merchandise, intopicking stock in the one or more levels of the storage structure 130 andthen selectively retrieve ordered case units for shipping the orderedcase units to, for example, a store or other suitable location. Thein-feed transfer stations 170 and out-feed transfer stations 160 mayoperate together with their respective multilevel vertical conveyors150A, 150B for bi-directionally transferring case units to and from oneor more levels of the storage structure 130. It is noted that while themultilevel vertical conveyors are described as being dedicated inboundconveyors 150A and outbound conveyors 150B, in alternate embodimentseach of the conveyors 150A, 150B may be used for both inbound andoutbound transfer of case units/case units from the storage andretrieval system.

It is noted that the multilevel vertical conveyors may be substantiallysimilar to those described in U.S. patent application Ser. No.12/757,354, entitled “LIFT INTERFACE FOR STORAGE AND RETRIEVALSYSTEMS,”previously incorporated by reference. For example, referring toFIGS. 2-5, it is noted that the input multilevel vertical conveyor 150Aand associated in-feed transfer stations 170 will be described, however,the out-feed multilevel vertical conveyors 150B and out-feed transferstations 160 may be substantially similar to that described below fortheir in-feed counterparts but for the direction of material flow out ofthe storage and retrieval system 100 rather than into the storage andretrieval system 100. As may be realized, the storage and retrievalsystem 100 may include multiple in-feed and out-feed multilevel verticalconveyors 150A, 150B that are accessible by, for example, bots 110 oneach level of the storage and retrieval system 100 so that one or morecase unit(s), uncontained or without containment (e.g. case unit(s) arenot sealed in trays), can be transferred from a multilevel verticalconveyor 150A, 150B to each storage space on a respective level and fromeach storage space to any one of the multilevel vertical conveyors 150A,150B on a respective level. The bots 110 may be configured to transferthe uncontained case units between the storage spaces and the multilevelvertical conveyors with one pick (e.g. substantially directly betweenthe storage spaces and the multilevel vertical conveyors). By way offurther example, the designated bot 110 picks the uncontained caseunit(s) from a shelf of a multilevel vertical conveyor, transports theuncontained case unit(s) to a predetermined storage area of the storagestructure 130 and places the uncontained case unit(s) in thepredetermined storage area (and vice versa).

Generally, the multilevel vertical conveyors include payload shelves 730(FIGS. 2A-4) attached to chains or belts that form continuously movingor circulating vertical loops (the shape of the loop shown in the Figs.is merely exemplary and in alternate embodiments the loop may have anysuitable shape including rectangular and serpentine) that move at asubstantially constant rate, so that the shelves 730 use what may bereferred to as the “paternoster” principle of continuous conveyance,with loading and unloading performed at any point in the loop withoutslowing or stopping. The multilevel vertical conveyors 150A, 150B may becontrolled by a server, such as for example, control server 120, or anyother suitable controller. One or more suitable computer workstations700 may be connected to the multilevel vertical conveyors 150A, 150B andthe server 120 in any suitable manner (e.g. wired or wirelessconnection) for providing, as an example, inventory management,multilevel vertical conveyor functionality and control, and customerorder fulfillment. As may be realized, the computer workstations 700and/or server 120 may be programmed to control the in-feed and/orout-feed conveyor systems. In alternate embodiments, the computerworkstations 700 and/or server 120 may also be programmed to control thetransfer stations 140. In one exemplary embodiment, one or more of theworkstations 700 and control server 120 may include a control cabinet, aprogrammable logic controller and variable frequency drives for drivingthe multilevel vertical conveyors 150A, 150B. In alternate embodimentsthe workstations 700 and/or control server 120 may have any suitablecomponents and configuration. In one exemplary embodiment, theworkstations 700 may be configured to substantially remedy anyexceptions or faults in the in-feed and/or out-feed conveyor systemssubstantially without operator assistance and communicate fault recoveryscenarios with the control server 120 and/or vice versa.

Referring also to FIG. 4, in this exemplary embodiment, the multilevelvertical conveyors 150A may include a frame 710 configured to supportdriven members such as, for example, chains 720. The chains 720 may becoupled to the shelves 730, which are movably mounted to the frame 710such that the chains 720 effect substantially continuous movement of theshelves 730 around the frame 710. In alternate embodiments, any suitabledrive link, such as for example, belts or cables may be used to drivethe shelves 730. Each shelf 730 may include, for example, supports 930and a platform 900. The supports 930 may extend from the platform 900and be configured for attaching and mounting the shelf 730 to, forexample, one or more drive chains 720. The platform 900 may include, forexample, any suitably shaped frame 911, which in this example isgenerally “U” shaped (e.g. having lateral members connected by a spanmember at one end), and has any suitable number of spaced apart fingers910 extending from the frame 911. The fingers 910 may be configured forsupporting the pickfaces 750, 752 (FIG. 2B) where each pickfacecomprises at least one uncontained case unit. In one exemplaryembodiment, each of the fingers 910 may be removably fastened to a frame911 for facilitating replacement or repair of individual fingers 910.The fingers 910, frame 911 (and supports 930) may form an integralstructure or platform that defines the seating surface that contacts andsupports the uncontained case units. It is noted that the shelf 730illustrates only a representative structure and in alternateembodiments, the shelves 730 may have any suitable configuration andsize for transporting pickfaces 750, 752. The spaced apart fingers 910are configured to interface with, for example, a transfer arm oreffector 1235 of the bots 110 and the in-feed transfer stations 170 fortransferring the pickfaces 750, 752 between the multilevel verticalconveyor 150A and one or more of the transfer stations 170 and bots 110.In alternate embodiments, the spaced apart fingers 910 may be configuredto interface with bot transfer stations 140 as described below.

The multilevel vertical conveyors 150A may also include a suitablestabilizing device(s), such as for example, driven stabilizing chainsfor stabilizing the shelves 730 during vertical travel. In one example,the stabilizing devices may include chain driven dogs that are engagedto the shelves in both the upward and downward directions to form, forexample, a three point engagement with the shelf supports 930. The drivechains 720 for the shelves 730 and stabilizing devices may be drivinglycoupled to for example, any suitable number of drive motors under thecontrol of, for example, one or more of the computer workstations 700and control server 120.

In one exemplary embodiment there may be any suitable number of shelves730 mounted and attached to the drive chains 720. As can be seen in FIG.2B each shelf 730 may be configured to carry, for exemplary purposesonly, two or more separate pickfaces 750750, 752 in correspondingpositions A, C on the shelf 730 (e.g. a single vertical conveyor isfunctionally, equivalent to multiple individually operated conveyorsarranged adjacent one another). In alternate embodiments, as can be seenin FIG. 5 the shelves 730′ may be configured to carry, for exemplarypurposes only, four separate pickfaces 750-753 in correspondingpositions A-D. In still other alternate embodiments, each shelf may beconfigured to carry more or less than four separate loads. As describedabove, each pickface may comprise one or more uncontained case units andmay correspond to the load of a single bot 110. As may be realized, thespace envelope or area platform of each pickface may be different. Byway of example, uncontained cases, such as those directly transported bythe multilevel vertical conveyors have various different sizes (e.g.differing dimensions). Also, as noted each pickface may include one ormore uncontained cases. Thus, the length and width of each pickfacecarried by the multilevel vertical conveyors may be different. Inalternate embodiments each pickface may be broken between, for example,bots 110 where different portions of the pickface are transported bymore than one bot 110 on, for example, different levels of the storagestructure 130. As may be realized when a pickface is broken each portionof the broken pickface may be considered as a new pickface by thestorage and retrieval system 100. For exemplary purposes only, referringto FIGS. 3A, 3B the shelves 730 of the multilevel vertical conveyors150A, 150B may be spaced from each other by a predetermined pitch P toallow for placement or removal of loads 810, 820 from the substantiallycontinuously moving shelves 730 as will be described below.

Referring now to FIG. 5, and as described above, the multilevel verticalconveyors, such as conveyor 150A are supplied with uncontained caseunits 1000 from in-feed transfer stations 170 (FIG. 1). As describedabove, the in-feed transfer stations 170 may include one or more ofdepalletizing workstations, conveyors 240, conveyor interfaces/bot loadaccumulators 1010A, 1010B and conveyor mechanisms 1030. As can be seenin FIG. 5, uncontained case units 1000 are moved from, for exampledepalletizing workstations by conveyors 240. In this example, each ofthe positions A-D is supplied by a respective in-feed transfer station.As may be realized, while the transfer of case units is being describedwith respect to shelves 730′ it should be understood that transfer ofcase units to shelves 730 occurs in substantially the same manner. Forexample, position A may be supplied by in-feed transfer station 170A andposition C may be supplied by in-feed transfer station 170B. Referringalso to FIG. 2A the in-feed transfer stations 170A, 170B, for supplyingsimilar sides of the shelf 730 (in this example positions A and C, whichare disposed side by side, form a first side 1050 of the shelf 730 andpositions B and D, which are disposed side by side, form a second side1051 of the shelf 730), may be located one above the other in ahorizontally staggered stacked arrangement (an exemplary stackedarrangement is shown in FIG. 2A). In other exemplary embodiments, thestacked arrangement may be configured so that the in-feed transferstations are disposed vertically in-line one above the other and extendinto the multilevel vertical conveyors by different amounts forsupplying, for example, positions A and B or positions C and D wherepositions A and B (and positions C and D) are disposed one in front ofthe other, rather than side by side. In alternate embodiments, thein-feed transfer stations may have any suitable configuration andpositional arrangement. As can be seen in FIG. 5, the first side 1050and second side 1051 of the shelf 730 are loaded (and unloaded) inopposing directions such that each multilevel vertical conveyor 150A islocated between respective transfer areas 295A, 295B where the firstside 1050 interfaces with a transfer area 295B and the second side 1051interfaces with transfer area 295A.

In this exemplary embodiment, the accumulators 1010A, 1010B areconfigured to form the uncontained case units 1000 into the individualbot pickfaces 750-753 prior to loading a respective position A-D on themultilevel vertical conveyor 730. In one exemplary embodiment, thecomputer workstation 700 and/or control server 120 may provideinstructions or suitably control the accumulators 1010A, 1010B (and/orother components of the in-feed transfer stations 170) for accumulatinga predetermined number of case units to form the pickfaces 750-753. Theaccumulators 1010A, 1010B may align the case units in any suitablemanner (e.g. making one or more sides of the case units flush, etc.)and, for example, abut the case units together. The accumulators 1010A,1010B may be configured to transfer the pickfaces 750-753 to respectiveconveyor mechanisms 1030 for transferring the pickfaces 750-753 to arespective shelf position A-D. In one exemplary embodiment the conveyormechanisms 1030 may include belts or other suitable feed devices formoving the pickfaces 750-753 onto transfer platforms 1060. The transferplatforms 1060 may include spaced apart fingers for supporting thepickfaces 750-753 where the fingers 910 of the shelves 730 areconfigured to pass between the fingers of the transfer platforms 1060for lifting (or placing) the pickfaces 750-753 from the transferplatforms 1060. In another exemplary embodiment, the fingers of thetransfer platforms 1060 may be movable and serve to insert the pickfaces750-753 into the path of the shelves 730 in a manner similar to thatdescribed below with respect to the bot transfer stations 140. Inalternate embodiments the in-feed transfer stations 170 (and out-feedtransfer stations 160) may be configured in any suitable manner fortransferring case units (e.g. the pickfaces formed by the case units)onto or from respective multilevel vertical conveyors 150A, 150B.

In an alternate embodiment, the bots 110 may interface directly with themultilevel vertical conveyors 150A, 150B while in alternate embodimentsthe bots 110 may interface indirectly with the multilevel verticalconveyors through, for example, respective bot transfer stations 140(which may have extendable fingers for interfacing with slatted supportshelves of the multi-level vertical conveyors which may be substantiallysimilar to those described in U.S. patent application Ser. No.12/757,354, entitled “LIFT INTERFACE FOR STORAGE AND RETRIEVALSYSTEMS,”previously incorporated by reference). It is noted that whilethe interface between the bot transfer stations 140 and the multilevelvertical conveyors 150A, 150B are described it should be understood thatinterfacing between the bots 110 and the multilevel vertical conveyors150A, 150B occurs in a substantially similar manner (e.g. as describedin U.S. patent application Ser. No. 12/757,312, entitled “AUTONOMOUSTRANSPORTS FOR STORAGE AND RETRIEVAL SYSTEMS,” previously incorporatedby reference herein in its entirety). For exemplary purposes only,referring now to FIGS. 2B and 6A-6D, the multilevel vertical conveyors150A transfer pickfaces 750, 752 from, for example, the in-feed transferstations 170 (or any other suitable device or loading system) to, forexample, the bot transfer stations 140 associated with each of thelevels in the storage structure 130. In other examples, the pickfaces750, 752 may be transferred directly from the multilevel verticalconveyors 150A to the bots 110 as described below. As may be realized,the bot transfer stations 140 are disposed on respective levels of thestorage structure adjacent the path of travel of the shelves 730 of arespective multilevel vertical conveyor 150A. In one exemplaryembodiment, there may be a bot transfer station 140 corresponding toeach of the positions A and C on the shelves 730 (and positions A-D withrespect to shelf 730′). For example, a first bot transfer station 140may remove pickface 750 from position A on shelf 730 while another bottransfer station 140 may remove pickface 750 from position C on shelf730 and so on. In other exemplary embodiments, one bot transfer station140 may serve to remove or place case units in more than one position A,C on the shelves 730. For example, one bot transfer station 140 may beconfigured for removing loads 750, 752 from one or more of positions A,C of shelf 730. In alternate embodiments, referring also to FIG. 5, onebot transfer station 140 may be configured for removing pickfaces 750,752 from one or more of positions A, C on a first side 1050 of the shelf730′ while another bot transfer station 140 may be configured to removepickfaces 751, 753 from one or more of positions B, D on the second side1051 of the shelf 730′. In alternate embodiments the bot transferstations 140 may have any suitable configuration for accessing anysuitable number of positions A-D of the shelves 730, 730′.

Each bot transfer station 140 may include a frame 1100, one or moredrive motors 1110 and a carriage system 1130. The frame 1100 may haveany suitable configuration for coupling the bot transfer station 140 to,for example, any suitable supporting feature of the storage structure130, such as a horizontal or vertical support. The carriage system 1130may be movably mounted to the frame 1100 through, for example, rails1120 that are configured to allow the carriage system 1130 to movebetween retracted and extended positions as shown in FIGS. 6A and 6B.The carriage system 1130 may include a carriage base 1132 and fingers1135. The fingers 1135 may be mounted to the carriage base 1132 in aspaced apart arrangement so that the fingers 1135 extend from thecarriage base 1132 in a cantilevered fashion. It is noted that eachfinger 1135 may be removably mounted to the carriage base 1132 forfacilitating replacement or repair of individual fingers 1135. Inalternate embodiments the fingers and carriage base may be of unitaryone-piece construction. The fingers 1135 of the bot transfer stations140 may be configured to pass between the fingers 910 (FIG. 4) of theshelves 730 of the multilevel vertical conveyors 150A (FIG. 1) forremoving pickfaces such as pickface 1150 (which may be substantiallysimilar to pickfaces 750-753) from the shelves 730. The bot transferstation 140 may also include a load positioning device 1140 thatretractably extends between, for example, the spaced apart fingers 1135in the direction of arrow 1181 for effecting positioning of the pickface1150 in a predetermined orientation relative to the bot transfer station140. In still other alternate embodiments the carriage system 1130 mayhave any suitable configuration and/or components. The one or more drivemotors 1110 may be any suitable motors mounted to the frame 1100 forcausing the extension/retraction of the carriage system 1130 and theextension/retraction of the positioning device 1140 in any suitablemanner such as by, for exemplary purposes only, drive belts or chains.In alternate embodiments, the carriage system and positioning device maybe extended and retracted in any suitable manner.

In operation, referring also to FIGS. 2C, 2D, 3A and 3B, inboundpickfaces (e.g. pickfaces, which include one or more case units, thatare being transferred into the storage and retrieval system) such aspickface 1150 will circulate around the multilevel vertical conveyor150A and be removed from a respective conveyor by, for example, a bot110. In one example, the pickface 1150 may be loaded onto the shelves730 during an upward travel of the multilevel vertical conveyor 150A andoff loaded from the shelves 730 during downward travel of the multilevelvertical conveyor 150A. In alternate embodiments the pickfaces may beloaded or off loaded from the shelves 730 in any suitable manner. As maybe realized, the position of the case units on the multilevel verticalconveyor shelf 730 defines the pickface position that the bot 110 picksfrom. The bot may be configured to pick any suitable load or pickfacefrom the shelf 730 regardless of the pickface position on the shelf 730or the size of the pickface. In one exemplary embodiment, the storageand retrieval system 100 may include a bot positioning system forpositioning the bot adjacent the shelves 730 for picking a desiredpickface from a predetermined one of the shelves 730 (e.g. the bot 110is positioned so as to be aligned with the pickface). The botpositioning system may also be configured to correlate the extension ofthe bot transfer arm 1235 with the movement (e.g. speed and location) ofthe shelves 730 so that the transfer arm 1235 is extended and retractedto remove (or place) pickfaces from predetermined shelves 730 of themultilevel vertical conveyors 150A, 150B. For exemplary purposes only,the bot 110 may be instructed by, for example, the computer workstation700 or control server 120 (FIG. 2A) to extend the transfer arm 1235 (seealso FIGS. 11A-11D) into the path of travel of the pickface 1150. As thepickface 1150 is carried by the multilevel vertical conveyor 150A in thedirection of arrow 860 fingers 1235A (which may be substantially similarto fingers 1135 of the bot transfer station 140) of the bot transfer arm1235 pass through the fingers 910 of the shelf 730 for transferring thepickface 1150 from the shelf 730 to the transfer arm 1235 (e.g. thepickface 1150 is lifted from the fingers 910 via relative movement ofthe shelf 730 and the transfer arm 1235). As may be realized, the pitchP between shelves may be any suitable distance for allowing the transferof pickfaces between the multilevel vertical conveyor and the bots 110while the shelves 730 are circulating around the multilevel verticalconveyor at a substantially continuous rate. The bot transfer arm 1235may be retracted (in a manner substantially similar to that shown inFIGS. 6C, 6D with respect to the bot transfer station 140) so that thepickface 1150 is no longer located in the path of travel of the shelves730 of the multilevel vertical conveyor 150A. It is noted that inalternate embodiments, where the bot transfer stations 140 are used, thepositioning device 1140 may be extended through the fingers 1135 and thecarriage system 1130 (FIGS. 6A-6D) may be moved in the direction ofarrow 1180 for abutting the pickface 1150 against the positioning device1140 effecting positioning of the pickface 1150 in a predeterminedorientation relative to, for example, the bot transfer station 140. Thecarriage system 1130 may be fully retracted as shown in FIG. 6D fortransfer of the pickface 1150 to a bot 110.

Referring to FIGS. 2D and 3B, for transferring loads in the outbounddirection (e.g. moving pickfaces from or out of the storage andretrieval system) a pickface, such as pickface 1150, may be extendedinto the path of the shelves 730 of the multilevel vertical conveyor150B (which is substantially similar to conveyor 150A) by the bottransfer arm 1235 through an extension of the transfer arm 1235 relativeto a frame of the bot 110. The substantially continuous rate of movementof the shelves 730 in the direction of arrow 870 cause the fingers 910of the shelf 730 to pass through the fingers 1235A of the bot transferarm 1235 such that the movement of the shelf 730 effects lifting thepickface 1150 from the fingers 1235A. The pickface 1150 travels aroundthe multilevel vertical conveyor 150B to an out-feed transfer station160 (which is substantially similar to in-feed transfer station 170)where is it removed from the shelf 730 by a conveyor mechanism 1030 in amanner substantially similar to that described above.

It is noted that the respective transfer of pickfaces between themultilevel vertical conveyors 150A, 150B and the in-feed and out-feedtransfer stations 170, 160 may occur in a manner substantially similarto that described above with respect to the bots 110 and bot transferstations 140. In alternate embodiments transfer of pickfaces between themultilevel vertical conveyors 150A, 150B and the in-feed and out-feedtransfer stations 170, 160 may occur in any suitable manner.

As can be seen in FIGS. 2C and 2D the shelves 730 of the multilevelvertical conveyors 150A, 150B are loaded and unloaded by the in-feed andout-feed transfer stations 170, 160 and the bots 110 from a common sideof the shelf 730. For example, the shelves are loaded and unloaded inthe common direction 999 (e.g. from only one side of the shelf 730). Inthis example, to facilitate loading the multilevel vertical conveyorfrom only one side of the shelf, the multilevel vertical conveyors 150A,150B circumscribe a respective one of the in-feed and out-feed transferstations 170, 160 so that the pickfaces 1150 travel around the in-feedand out-feed transfer stations 170, 160. This allows the in-feed andout-feed transfer stations 170, 160 to be placed on the same side of theshelves 730 as the bots 110 for transferring pickfaces (and the caseunits therein) to and from the multilevel vertical conveyors 150A, 150B.

The bots may be substantially similar to those described in U.S. patentapplication Ser. No. 12/757,312, entitled “AUTONOMOUS TRANSPORTS FORSTORAGE AND RETRIEVAL SYSTEMS,”previously incorporated by referenceherein. For example, referring now to FIGS. 7-11D, the bots 110 thattransfer loads between, for example, the multilevel vertical conveyors150A, 150B and the storage shelves of a respective level of storagestructure 130 will be described. It is noted that in one exemplaryembodiment the bots 110 may transfer loads directly to and/or from themultilevel vertical conveyors 150A, 150B in a manner substantiallysimilar to that described with respect to the bot transfer stations 140.In one example, the bots 110 may be configured for substantiallycontinuous operation. For exemplary purposes only, the bots 110 may havea duty cycle of about ninety-five (95) percent. In alternate embodimentsthe bots may have any suitable duty cycle and operational periods.

As can be seen in FIG. 7, the bots 110 generally include a frame 1200, adrive system 1210, a control system 1220, and a payload area 1230. Thedrive system 1210 and control system 1220 may be mounted to the frame inany suitable manner. The frame may form the payload area 1230 and beconfigured for movably mounting a transfer arm or effector 1235 to thebot 110.

In one exemplary embodiment, the drive system 1210 may include two drivewheels 1211, 1212 disposed at a drive end 1298 of the bot 110 and twoidler wheels 1213, 1214 disposed at a driven end 1299 of the bot 110.The wheels 1211-1214 may be mounted to the frame 1200 in any suitablemanner and be constructed of any suitable material, such as for example,low-rolling-resistance polyurethane. In alternate embodiments the bot110 may have any suitable number of drive and idler wheels. In oneexemplary embodiment, the wheels 1211-1214 may be substantially fixedrelative to a longitudinal axis 1470 (FIG. 9B) of the bot 110 (e.g. therotational plane of the wheels is fixed in a substantially parallelorientation relative to the longitudinal axis 1470 of the bot) to allowthe bot 110 to move in substantially straight lines such as when, forexample, the bot is travelling on a transfer deck 130B, 330A, 330B (e.g.FIGS. 13-15, 18-19B) or within a picking isle 130A (e.g. FIGS. 13-15,18-19B). In alternate embodiments, the rotational plane of one or moreof the drive wheels and idler wheels may be pivotal (e.g. steerable)relative to the longitudinal axis 1470 of the bot for providing steeringcapabilities to the bot 110 by turning the rotational planes of one ormore of the idler or drive wheels relative to the longitudinal axis1470. The wheels 1211-1214 may be substantially rigidly mounted to theframe 1200 such that the axis of rotation of each wheel is substantiallystationary relative to the frame 1200. In alternate embodiments thewheels 1211-1214 may be movably mounted to the frame by, for example,any suitable suspension device, such that the axis of rotation of thewheels 1211-1214 is movable relative to the frame 1200. Movably mountingthe wheels 1211-1214 to the frame 1200 may allow the bot 110 tosubstantially level itself on uneven surfaces while keeping the wheels1211-1214 in contact with the surface.

Each of the drive wheels 1211, 1212 may be individually driven by arespective motor 1211M, 1212M. The drive motors 1211M, 1212M may be anysuitable motors such as, for exemplary purposes only, direct currentelectric motors. The motors 1211M, 1212M may be powered by any suitablepower source such as by, for example, a capacitor 1400 (FIG. 9B) mountedto the frame 1200. In alternate embodiments the power source may be anysuitable power source such as, for example, a battery or fuel cell. Instill other alternate embodiments the motors may be alternating currentelectric motors or internal combustion motors. In yet another alternateembodiment, the motors may be a single motor with dual independentlyoperable drive trains/transmissions for independently driving each drivewheel. The drive motors 1211M, 1212M may be configured forbi-directional operation and may be individually operable under, forexample, control of the control system 1220 for effecting steering ofthe bot 110 as will be described below. The motors 1211M, 1212M may beconfigured for driving the bot 110 at any suitable speed with anysuitable acceleration when the bot is in either a forward orientation(e.g. drive end 1298 trailing the direction of travel) or a reverseorientation (e.g. drive end 1298 leading the direction of travel). Inthis exemplary embodiment, the motors 1211M, 1212M are configured fordirect driving of their respective drive wheel 1211, 1212. In alternateembodiments, the motors 1211M, 1212M may be indirectly coupled to theirrespective wheels 1211, 1212 through any suitable transmission such as,for example, a drive shaft, belts and pulleys and/or a gearbox. Thedrive system 1210 of the bot 110 may include an electrical brakingsystem such as for example, a regenerative braking system (e.g. tocharge, for example, a capacitor 1400 (FIG. 9B) powering the bot 110under braking). In alternate embodiments, the bot 110 may include anysuitable mechanical braking system. The drive motors may be configuredto provide any suitable acceleration/deceleration rates and any suitablebot travel speeds. For exemplary purposes only the motors 1211M, 1212Mmay be configured to provide the bot (while the bot is loaded at fullcapacity) a rate of acceleration/deceleration of about 3.048 m/sec², atransfer deck 130B cornering speed of about 1.524 m/sec and a transferdeck straightaway speed of about 9.144 m/sec or about 10 m/sec.

As noted above drive wheels 1211, 1212 and idler wheels 1213, 1214 aresubstantially fixed relative to the frame 1200 for guiding the bot 110along substantially straight paths while the bot is travelling on, forexample, the transfer decks 130B, 330A, 330B (e.g. FIGS. 13-15, 18-19B).Corrections in the straight line paths may be made through differentialrotation of the drive wheels 1211, 1212 as described herein. Inalternate embodiments, guide rollers 1250, 1251 may be mounted to theframe to aid in guiding the bot 110 on the transfer deck 130B such asthrough contact with a wall 1801, 2100 (FIG. 18-19B) of the transferdeck 130B. However, in this exemplary embodiment the fixed drive andidler wheels 1211-1214 may not provide agile steering of the bot 110such as when, for example, the bot 110 is transitioning between thepicking aisles 130A, transfer decks 130B or transfer areas 295. In oneexemplary embodiment, the bot 110 may be provided with one or moreretractable casters 1260, 1261 for allowing the bot 110 to make, forexample, substantially right angle turns when transitioning between thepicking aisles 130A, transfer decks 130B and transfer areas 295. It isnoted that while two casters 1260, 1261 are shown and described, inalternate embodiments the bot 110 may have more or less than tworetractable casters. The retractable casters 1260, 1261 may be mountedto the frame 1200 in any suitable manner such that when the casters1260, 1261 are in a retracted position both the idler wheels 1213, 1214and drive wheels 1211, 1212 are in contact with a flooring surface suchas surface 1300S of the rails 1300 or a transfer deck 130B of thestorage structure 130, whereas when the casters 1260, 1261 are loweredthe idler wheels 1213, 1214 are lifted off the flooring surface. As thecasters 1260, 1261 are extended or lowered the idler wheels 1213, 1214are lifted off of the flooring surface so that the driven end 1299 ofthe bot 110 can be pivoted about a point P (FIGS. 9B, 19A, 19B) of thebot through, for example, differential rotation of the drive wheels1211, 1212. For example, the motors 1211M, 1212M may be individually anddifferentially operated for causing the bot 110 to pivot about point Pwhich is located, for example, midway between the wheels 1211, 1212while the driven end 1299 of the bot swings about point P accordinglyvia the casters 1260, 1261.

In other exemplary embodiments, the idler wheels 1213, 1214 may bereplaced by non-retractable casters 1260′, 1261′ (FIG. 9C) where thestraight line motion of the bot 110 is controlled by differingrotational speeds of each of the drive wheels 1211, 1212 as describedherein. The non-retractable casters 1260′, 1261′ may be releasablylockable casters such that the casters 1260′, 1261′ may be selectivelylocked in predetermined rotational orientations to, for example, assistin guiding the bot 110 along a travel path. For example, during straightline motion of the bot 110 on the transfer deck 130B and/or within thepicking aisles 130A the non-retractable casters 1260′, 1261′ may belocked in an orientation such that the wheels of the casters 1260′,1261′ are substantially in-line with a respective one of the drivewheels 1213, 1214 (e.g. the rotational plane of the wheels of thecasters is fixed in a substantially parallel orientation relative to thelongitudinal axis 1470 of the bot). The rotational plane of the wheelsof the non-retractable casters 1260′, 1261′ may be locked and releasedrelative to the longitudinal axis 1470 of the bot 110 in any suitablemanner. For example, a controller 1701 (FIG. 12) of the bot 110 may beconfigured to effect the locking and releasing of the casters 1260′,1261′ by for example controlling any suitable actuator and/or lockingmechanism. In alternate embodiments any other suitable controllerdisposed on or remotely from the bot 110 may be configured to effect thelocking and releasing of the casters 1260′, 1261′.

The bot 110 may also be provided with guide wheels 1250-1253. As can bebest seen in FIGS. 8B and 8C, while the bot 110 is travelling in, forexample, the picking aisles 130A and/or transfer areas 295 the movementof the bot 110 may be guided by a tracked or rail guidance system. Therail guidance system may include rails 1300 disposed on either side ofthe bot 110. The rails 1300 and guide wheels 1250-1253 may allow forhigh-speed travel of the bot 110 without complex steering and navigationcontrol subsystems. The rails 1300 may be configured with a recessedportion 1300R shaped to receive the guide wheels 1250-1253 of the bot110. In alternate embodiments the rails may have any suitableconfiguration such as, for example, without recessed portion 1300R. Therails 1300 may be integrally formed with or otherwise fixed to, forexample, one or more of the horizontal and vertical supports 398, 399 ofthe storage rack structure 130. As can be seen in FIG. 8C the pickingaisles may be substantially floor-less such that bot wheel supports1300S of the guide rails 1300 extend away from the storage areas apredetermined distance to allow a sufficient surface area for the wheels1211-1214 (or in the case of lockable casters, wheels 1260′, 1261′) ofthe bot 110 to ride along the rails 1300. In alternate embodiments thepicking aisles may have any suitable floor that extends between adjacentstorage areas on either side of the picking aisle. In one exemplaryembodiment, the rails 1300 may include a friction member 1300F forproviding traction to the drive wheels 1211, 1212 of the bot 110. Thefriction member 1300F may be any suitable member such as for example, acoating, an adhesive backed strip or any other suitable member thatsubstantially creates a friction surface for interacting with the wheelsof the bot 110.

While four guide wheels 1250-1253 are shown and described it should beunderstood that in alternate embodiments the bot 110 may have anysuitable number of guide wheels. The guide wheels 1250-1253 may bemounted to, for example, the frame 1200 of the bot in any suitablemanner. In one exemplary embodiment, the guide wheels 1250-1253 may bemounted to the frame 1200, through for example, spring and damperdevices so as to provide relative movement between the guide wheels1250-1253 and the frame 1200. The relative movement between the guidewheels 1250-1253 and the frame may be a dampening movement configuredto, for example, cushion the bot 110 and its payload against any changein direction or irregularities (e.g. misaligned joints between tracksegments, etc.) in the track 1300. In alternate embodiments, the guidewheels 1250-1253 may be rigidly mounted to the frame 1200. The fitmentbetween the guide wheels 1250-1253 and the recessed portion 1300R of thetrack 1300 may be configured to provide stability (e.g. anti-tipping) tothe bot during, for example, cornering and/or extension of the transferarm 1235 (e.g. to counteract any tipping moments created by acantilevered load on the transfer arm). In alternate embodiments the botmay be stabilized in any suitable manner during cornering and/orextension of the transfer arm 1235. For example, the bot 110 may includea suitable counterweight system for counteracting any moment that iscreated on the bot through the extension of the transfer arm 1235.

The transfer arm 1235 may be movably mounted to the frame 1200 within,for example, the payload area 1230. It is noted that the payload area1230 and transfer arm 1235 may be suitably sized for transporting casesin the storage and retrieval system 100. For example, the width W of thepayload area 1230 and transfer arm 1235 may be substantially the same asor larger than a depth D (FIG. 11B) of the storage shelves 600. Inanother example, the length L of the payload area 1230 and transfer arm1235 may be substantially the same as or larger than the largest itemlength transferred through the system 100 with the item length beingoriented along the longitudinal axis 1470 (FIG. 9B) of the bot 110.

Referring also to FIGS. 9A and 9B, in this exemplary embodiment thetransfer arm 1235 may include an array of fingers 1235A, one or morepusher bars 1235B and a fence 1235F. In alternate embodiments thetransfer arm may have any suitable configuration and/or components. Thetransfer arm 1235 may be configured to extend and retract from thepayload area 1230 for transferring loads to and from the bot 110. In oneexemplary embodiment, the transfer arm 1235 may be configured to operateor extend in a unilateral manner relative to the longitudinal axis 1470of the bot (e.g. extend from one side of the bot in direction 1471) forincreasing, for example, reliability of the bot while decreasing thebots complexity and cost. It is noted that where the transfer arm 1235is operable only to one side of the bot 110, the bot may be configuredto orient itself for entering the picking aisles 130A and/or transferareas 295 with either the drive end 1298 or the driven end 1299 facingthe direction of travel so that the operable side of the bot is facingthe desired location for depositing or picking a load. In alternateembodiments the bot 110 may be configured such that the transfer arm1235 is operable or extendable in a bilateral manner relative to thelongitudinal axis 1470 of the bot (e.g. extendable from both sides ofthe bot in directions 1471 and 1472).

In one exemplary embodiment, the fingers 1235A of the transfer arm 1235may be configured such that the fingers 1235A are extendable andretractable individually or in one or more groups. For example, eachfinger may include a locking mechanism 1410 that selectively engageseach finger 1235A to, for example, the frame 1200 of the bot 110 or amovable member of the transfer arm 1235 such as the pusher bar 1235B.The pusher bar 1235B (and any fingers coupled to the pusher bar), forexample, may be driven by any suitable drive such as extension motor1495. The extension motor 1495 may be connected to, for example, thepusher bar, through any suitable transmission such as, for exemplarypurposes only, a belt and pulley system 1495B (FIG. 9A).

In one exemplary embodiment, the locking mechanism for coupling thefingers 1235A to, for example, the pusher bar 1235B may be, for example,a cam shaft driven by motor 1490 that is configured to causeengagement/disengagement of each finger with either the pusher bar orframe. In alternate embodiments, the locking mechanism may includeindividual devices, such as solenoid latches associated withcorresponding ones of the fingers 1235A. It is noted that the pusher barmay include a drive for moving the pusher bar in the direction of arrows1471, 1472 for effecting, for example, a change in orientation (e.g.alignment) of a load being carried by the bot 110, gripping a load beingcarried by the bot 110 or for any other suitable purpose. In oneexemplary embodiment, when one or more locking mechanisms 1410 areengaged with, for example, the pusher bar 1235B the respective fingers1235A extend and retract in the direction of arrows 1471, 1472substantially in unison with movement of the pusher bar 1235B while thefingers 1235A whose locking mechanisms 1410 are engaged with, forexample, the frame 1200 remain substantially stationary relative to theframe 1200.

In another exemplary embodiment, the transfer arm 1235 may include adrive bar 1235D or other suitable drive member. The drive bar 1235D maybe configured so that it does not directly contact a load carried on thebot 110. The drive bar 1235D may be driven by a suitable drive so thatthe drive bar 1235D travels in the direction of arrows 1471, 1472 in amanner substantially similar to that described above with respect to thepusher bar 1235B. In this exemplary embodiment, the locking mechanisms1410 may be configured to latch on to the drive bar 1235D so that therespective fingers 1235A may be extended and retracted independent ofthe pusher bar and vice versa. In alternate embodiments the pusher bar1235B may include a locking mechanism substantially similar to lockingmechanism 1410 for selectively locking the pusher bar to either thedrive bar 1235D or the frame 1200 where the drive bar is configured tocause movement of the pusher bar 1235B when the pusher bar 1235B isengaged with the drive bar 1235D.

In one exemplary embodiment, the pusher bar 1235B may be a one-piece barthat spans across all of the fingers 1235A. In other exemplaryembodiments, the pusher bar 1235B may be a segmented bar having anysuitable number of segments 1235B1, 1235B2. Each segment 1235B1, 1235B2may correspond to the groups of one or more fingers 1235A such that onlythe portion of the pusher bar 1235B corresponding to the finger(s) 1235Athat are to be extended/retracted is moved in the direction of arrows1471, 1472 while the remaining segments of the pusher bar 1235B remainstationary so as to avoid movement of a load located on the stationaryfingers 1235A.

The fingers 1235A of the transfer arm 1235 may be spaced apart from eachother by a predetermined distance so that the fingers 1235A areconfigured to pass through or between corresponding support legs 620L1,620L2 of the storage shelves 600 (FIG. 5A) and corresponding supportfingers of the shelves on the multilevel vertical conveyors 150A, 150B.In alternate embodiments, the fingers 1235A may also be configured topass through item support fingers of the bot transfer stations 140. Thespacing between the fingers 1235A and a length of the fingers of thetransfer arm 1235 allows an entire length and width of the loads beingtransferred to and from the bot 110 to be supported by the transfer arm1235.

The transfer arm 1235 may include any suitable lifting device(s) 1235Lconfigured to move the transfer arm 1235 in a direction substantiallyperpendicular to a plane of extension/retraction of the transfer arm1235.

Referring also to FIGS. 10A-10C, in one example, a load (substantiallysimilar to pickfaces 750-753) is acquired from, for example, a storageshelf 600 by extending the fingers 1235A of the transfer arm 1235 intothe spaces 620S between support legs 620L1, 620L2 of the storage shelf600 and under one or more target case units 1500 located on the shelf600. The transfer arm lift device 1235L is suitably configured to liftthe transfer arm 1235 for lifting the one or more target case units 1500off of the shelf 600. The fingers 1235A are retracted so that the one ormore target case units are disposed over the payload area 1230 of thebot 110. The lift device 1235L lowers the transfer arm 1235 so the oneor more target case units are lowered into the payload area 1230 of thebot 110. In alternate embodiments, the storage shelves 600 may beconfigured with a lift motor for raising and lowering the target caseunits where the transfer arm 1235 of the bot 110 does not include a liftdevice 1235L. FIG. 10B illustrates an extension of three of the fingers1235A for transferring a case unit 1501. FIG. 10C shows a shelf 1550having two case units 1502, 1503 located side by side. In FIG. 10C,three fingers 1235A of the transfer arm 1235 are extended for acquiringonly case unit 1502 from the shelf 1550. As can be seen in FIG. 100, itis noted that the pickfaces carried by the bots 110 may include cases ofindividual case units (e.g. case unit 1502 includes two separate boxesand case unit 1503 includes three separate boxes). It is also noted thatin one exemplary embodiment the extension of the transfer arm 1235 maybe controlled for retrieving a predetermined number of case units froman array of case units. For example, the fingers 1235A in FIG. 100 maybe extended so that only item 1502A is retrieved while item 1502Bremains on the shelf 1550. In another example, the fingers 1235A may beextended only part way into a shelf 600 (e.g. an amount less than thedepth D of the shelf 600) so that a first item located at, for example,the front of the shelf (e.g. adjacent the picking aisle) is picked whilea second item located at the back of the shelf, behind the first item,remains on the shelf.

As noted above the bot 110 may include a retractable fence 1235F.Referring to FIGS. 11A-11D, the fence 1235F may be movably mounted tothe frame 1200 of the bot 110 in any suitable manner so that the loads,such as case unit 1600, pass over the retracted fence 1235F as the loadsare transferred to and from the bot payload area 1230 as can be seen inFIG. 11A. Once the case unit 1600 is located in the payload area 1230,the fence 1235F may be raised or extended by any suitable drive motor1610 so that the fence 1235F extends above the fingers 1235A of the bot110 for substantially preventing the case unit 1600 from moving out ofthe payload area 1230 as can be seen in FIG. 11B. The bot 110 may beconfigured to grip the case unit 1600 to, for example, secure the loadduring transport. For example, the pusher bar 1235B may move in thedirection of arrow 1620 towards the fence 1235F such that the case unit1600 is sandwiched or gripped between the pusher bar 1235B and the fence1235F as can be seen in FIGS. 11C and 11D. As may be realized, the bot110 may include suitable sensors for detecting a pressure exerted on thecase unit 1600 by the pusher bar 1235B and/or fence 1235F so as toprevent damaging the case unit 1600. In alternate embodiments, the caseunit 1600 may be gripped by the bot 110 in any suitable manner.

Referring again to FIGS. 9B and 9C, the bot 110 may include a roller bed1235RB disposed in the payload area 1230. The roller bed 1235RB mayinclude one or more rollers 1235R disposed transversely to thelongitudinal axis 1470 of the bot 110. The rollers 1235R may be disposedwithin the payload area 1230 such that the rollers 1235R and the fingers1235A are alternately located so that the fingers 1235A may pass betweenthe rollers 1235R for transferring case units to and from the payloadarea 1230 as described above. One or more pushers 1235P may be disposedin the payload area 1230 such that a contact member of the one or morepushers 1235P extends and retracts in a direction substantiallyperpendicular to the axis of rotation of the rollers 1235R. The one ormore pushers 1235P may be configured to push the case unit 1600 back andforth within the payload area 1230 in the direction of arrow 1266 (e.g.substantially parallel to the longitudinal axis 1470 of the bot 110)along the rollers 1235R for adjusting a position of the case unit 1600longitudinally within the payload area 1230. In alternate embodiments,the rollers 1235R may be driven rollers such that a controller of, forexample, the bot drives the rollers for moving the case unit 1600 suchthat the load is positioned at a predetermined location within thepayload area 1230. In still other alternate embodiments the load may bemoved to the predetermined location within the payload area in anysuitable manner. The longitudinal adjustment of the case unit 1600within the payload area 1230 may allow for positioning of the loads 1600for transferring the loads from the payload area to, for example, astorage location or other suitable location such as the multilevelvertical conveyors 150A, 150B or in alternate embodiments the bottransfer stations 140.

Referring now to FIG. 12, the control system 1220 of the bot is shown.The control system 1220 may be configured to provide communications,supervisory control, bot localization, bot navigation and motioncontrol, case sensing, case transfer and bot power management. Inalternate embodiments the control system 1220 may be configured toprovide any suitable services to the bot 110. The control system 1220may include any suitable programs or firmware configured for performingthe bot operations described herein. The control system 1220 may beconfigured to allow for remote (e.g. over a network) debugging of thebot. In one example, the firmware of the bot may support a firmwareversion number that can be communicated over, for example, the network180 so the firmware may be suitably updated. The control system 1220 mayallow for assigning a unique bot identification number to a respectivebot 110 where the identification number is communicated over the network180 (FIG. 1) to, for example, track a status, position or any othersuitable information pertaining to the bot 110. In one example, the botidentification number may be stored in a location of the control system1220 such that the bot identification number is persistent across apower failure but is also changeable.

In one exemplary embodiment, the control system 1220 may be divided intoa front end 1220F (FIG. 7) and back end 1220B (FIG. 7) having anysuitable subsystems 1702, 1705. The control system 1220 may include anon-board computer 1701 having, for example, a processor, volatile andnon-volatile memory, communication ports and hardware interface portsfor communicating with the on-board control subsystems 1702, 1705. Thesubsystems may include a motion control subsystem 1705 and aninput/output subsystem 1702. In alternate embodiments, the bot controlsystem 1220 may include any suitable number of portions/subsystems.

The front end 1220F may be configured for any suitable communications(e.g. synchronous or asynchronous communications regarding bot commands,status reports, etc.) with the control server 120. The bot front end1220F may be configured as a pair of state machines where a first one ofthe state machines handles communication between the front end 1220F andthe control server 120 and a second one of the state machines handlescommunication between the front end 1220F and the back end 1220B. Inalternate embodiments the front end 1220F may have any suitableconfiguration. The back end 1220B may be configured to effect thefunctions of the bot described above (e.g. lowering the casters,extending the fingers, driving the motors, etc.) based on, for example,the primitives received from the front end 1220F. In one example, theback end 122B may monitor and update bot parameters including, but notlimited to, bot position and velocity and send those parameters to the,bot front end 1220F. The front end 1220F may use the parameters (and/orany other suitable information) to track the bots 110 movements anddetermine the progress of the bot task(s). The front end 1220F may sendupdates to, for example, the bot proxy 2680 so that the control server120 can track the bot movements and task progress and/or any othersuitable bot activities.

The motion control subsystem 1705 may be part of the back end 1220B andconfigured to effect operation of, for example, the drive motors 1211M,1212M, 1235L, 1495, 1490, 1610 of the bot 110 as described herein. Themotion control subsystem 1705 may operatively connected to the computer1701 for receiving control instructions for the operation of, forexample, servo drives (or any other suitable motor controller) residentin the motion control subsystem 1705 and subsequently their respectivedrive motors 1211M, 1212M, 1235L, 1495, 1490, 1610. The motion controlsubsystem 1704 may also include suitable feedback devices, such as forexample, encoders, for gathering information pertaining to the drivemotor operation for monitoring, for example, movement the transfer arm1235 and its components (e.g. when the fingers 1235A are latched to thepusher bar, a location of the pusher bar, extension of the fence, etc.)or the bot 110 itself. For example, an encoder for the drive motors1211M, 1212M may provide wheel odometry information, and encoders forlift motor 1235L and extension motor 1495 may provide informationpertaining to a height of the transfer arm 1235 and a distance ofextension of the fingers 1235A. The motion control subsystem 1705 may beconfigured to communicate the drive motor information to the computer1701 for any suitable purpose including but not limited to adjusting apower level provided to a motor.

The input/output subsystem 1702 may also be part of the back end 1220Band configured to provide an interface between the computer 1701 and oneor more sensors 1710-1716 of the bot 110. The sensors may be configuredto provide the bot with, for example, awareness of its environment andexternal objects, as well as the monitor and control of internalsubsystems. For example, the sensors may provide guidance information,payload information or any other suitable information for use inoperation of the bot 110. For exemplary purposes only, the sensors mayinclude a bar code scanner 1710, slat sensors 1711, line sensors 1712,case overhang sensors 1713, arm proximity sensors 1714, laser sensors1715 and ultrasonic sensors 1716 as described in U.S. patent applicationSer. No. 12/757,312, entitled “AUTONOMOUS TRANSPORTS FOR STORAGE ANDRETRIEVAL SYSTEMS,”previously incorporated herein by reference.

It is noted that the computer 1701 and its subsystems 1702, 1705 may beconnected to a power bus for obtaining power from, for example, thecapacitor 1400 through any suitable power supply controller 1706. It isnoted that the computer 1701 may be configured to monitor the voltage ofthe capacitor 1400 to determine its state of charge (e.g. its energycontent). In one exemplary embodiment, the capacitor may be chargedthrough charging stations located at, for example, one or more transferstations 140 or at any other suitable location of the storage structure130 so that the bot is recharged when transferring payloads and remainsin substantially continuous use. The charging stations may be configuredto charge the capacitor 1400 within the time it takes to transfer thepayload of the bot 110. For exemplary purposes only, charging of thecapacitor 1400 may take about 15 seconds. In alternate embodiments,charging the capacitor may take more or less than about 15 seconds.During charging of the capacitor 1400 the voltage measurement may beused by the computer 1701 to determine when the capacitor is full and toterminate the charging process. The computer 1701 may be configured tomonitor a temperature of the capacitor 1400 for detecting faultconditions of the capacitor 1400.

The computer 1701 may also be connected to a safety module 1707 whichincludes, for example, an emergency stop device 1311 (FIG. 8A) whichwhen activated effects a disconnection of power to, for example, themotion control subsystem 1705 (or any other suitable subsystem(s) of thebot) for immobilizing or otherwise disabling the bot 110. It is notedthat the computer 1701 may remain powered during and after activation ofthe emergency stop device 1311. The safety module 1707 may also beconfigured to monitor the servo drives of the motion control subsystem1705 such that when a loss of communication between the computer and oneor more of the servo drives is detected, the safety module 1707 causesthe bot to be immobilized in any suitable manner. For example, upondetection of a loss of communication between the computer 1701 and oneor more servo drives the safety module 1707 may set the velocity of thedrive motors 1211M, 1212M to zero for stopping movement of the bot 110.

The communication ports of the control system 1220 may be configured forany suitable communications devices such as, for example, a wirelessradio frequency communication device 1703 (including one or moreantennae 1310) and any suitable optical communication device 1704 suchas, for example, an infrared communication device. The wireless radiofrequency communication device 1703 may be configured to allowcommunication between the bot 110 and, for example, the control server120 and/or other different bots 110 over any suitable wireless protocol.For exemplary purposes only, the wireless protocol for communicatingwith the control server 120 may be the wireless 802.11 network protocol(or any other suitable wireless protocol). Communications within the botcontrol system 1220 may be through any suitable communication bus suchas, for example, a control network area bus. It is noted that thecontrol server 120 and the bot control system 1220 may be configured toanticipate momentary network communication disruptions. For example, thebot may be configured to maintain operation as long as, for example, thebot 110 can communicate with the control server 120 when the bot 110transits a predetermined track segment and/or other suitable way point.The optical communication device 1704 may be configured to communicatewith, for example, the bot transfer stations for allowing initiation andtermination of charging the capacitor 1400. The bot 110 may beconfigured to communicate with other bots 110 in the storage andretrieval system 100 to form a peer-to-peer collision avoidance systemso that bots can travel throughout the storage and retrieval system 100at predetermined distances from each other in a manner substantiallysimilar to that described in U.S. patent application Ser. No.12/757,337, entitled “CONTROL SYSTEM FOR STORAGE AND RETRIEVALSYSTEMS,”previously incorporated by reference herein.

Referring again to FIG. 1, and as described above, the storage structure130 may include multiple levels of storage rack modules where each levelincludes an array of storage spaces (arrayed on the multiple levels andin multiple rows on each level), picking aisles 130A formed between therows of storage spaces, and transfer decks 130B. The picking aisles 130Aand transfer decks 130B being arranged for allowing the bots 110 totraverse respective levels of the storage structure 130 for placing caseunits into the picking stock and to retrieve the ordered case units. Thebots 110 may be configured to place case units, such as theabove-described retail merchandise, into picking stock in the one ormore levels of the storage structure 130 and then selectively retrieveordered case units for shipping the ordered case units to, for example,a store or other suitable location. As may be realized, the storage andretrieval system may be configured to allow random accessibility to thestorage spaces as will be described in greater detail below. Forexample, all storage spaces in the storage structure 130 may be treatedsubstantially equally when determining which storage spaces are to beused when picking and placing case units from/to the storage structure130 such that any storage space of sufficient size can be used to storecase units. The storage structure 130 of the exemplary embodiments mayalso be arranged such that there is no vertical or horizontal arraypartitioning of the storage structure. For example, each multilevelvertical conveyor 150A, 150B is common to all storage spaces (e.g. thearray of storage spaces) in the storage structure 130 such that any bot110 can access each storage space and any multilevel vertical conveyor150A, 150B can receive case units from any storage space on any level sothat the multiple levels in the array of storage spaces substantiallyact as a single level (e.g. no vertical partitioning). The multilevelvertical conveyors 150A, 150B can also receive case units from anystorage space on any level of the storage structure 130 (e.g. nohorizontal partitioning).

The storage structure 130 may also include charging stations 130C forreplenishing, for example, a battery pack of the bots 110. In oneexemplary embodiment, the charging stations 130C may be located at, forexample, the transfer areas 295 so that the bots 110 can substantiallysimultaneously transfer case units, for example, to and from amultilevel vertical conveyor 150A, 150B while being charged.

The bots 110 and other suitable features of the storage and retrievalsystem 100 may be controlled by, for example, one or more central systemcontrol computers (e.g. control server) 120 through, for example, anysuitable network 180. The network 180 may be a wired network, a wirelessnetwork or a combination of a wireless and wired network using anysuitable type and/or number of communication protocols. It is notedthat, in one exemplary embodiment, the system control server 120 may beconfigured to manage and coordinate the overall operation of the storageand retrieval system 100 and interface with, for example, a warehousemanagement system, which in turn manages the warehouse facility as awhole. The control server 120 may be substantially similar to thatdescribed in, for example, U.S. patent application Ser. No. 12/757,337,entitled “CONTROL SYSTEM FOR STORAGE AND RETRIEVAL SYSTEMS,”previouslyincorporated by reference herein in its entirety. For example, thecontrol server 120 may include a collection of substantiallyconcurrently running programs that are configured to manage the storageand retrieval system 100 including, for exemplary purposes only,controlling, scheduling, and monitoring the activities of all activesystem components, managing inventory and pickfaces, and interfacingwith a warehouse management system 2500. It is noted that a “pickface”as used herein may be one or more merchandise case units placed onebehind the other in a storage space or area of a storage shelf to beused in pick transactions for filling customer orders. In one example,all case units forming a given pickface are of the same stock keepingunit (SKU) and originally from the same pallet. In alternateembodiments, each pickface may include any suitable case units. Eachpickface may correspond to all or part of a bot load (e.g. the loadcarried by each bot 110 to and from the storage areas). Conversely, thebot load may be established based on a pickface determination. As may berealized the determination of the pickfaces may be variable within thestorage and retrieval system such that the size and locations of thepickface are dynamically changeable. It is also noted that interfacingwith the warehouse management system allows the control server 120 toreceive and execute pallet orders and to submit and executereplenishment orders as will be described below. The active systemcomponents may be the physical entities that act upon the case units tobe stored and retrieved. The active system components may include, as anon-limiting example, the bots, in-feed and out-feed stations,multilevel vertical conveyors, the network and user interface terminals.In alternate embodiments, the active system components may also includetransfer stations. The control server 120 may be configured to order theremoval of case units from the storage and retrieval system for anysuitable purpose, in addition to order fulfillment, such as, forexample, when case units are damaged, recalled or an expiration date ofthe case units has expired. In one exemplary embodiment, the controlserver 120 may be configured to give preference to case units that arecloser to their expiration date when fulfilling orders so those caseunits are removed from the storage and retrieval system before similarcase units (e.g. with the same SKU) having later expiration dates. Inthe exemplary embodiments, the distribution (e.g. sortation) of caseunits in the storage and retrieval system is such that the case units inthe can be provided for delivery to a palletizing station in anysuitable order at any desired rate using only two sortation sequences.The control server 120 may also be configured to incorporate, forexample, store plan rules when fulfilling orders so that the cases areprovided by the bots 110 to respective multilevel vertical conveyors150B in a first predetermined sequence (e.g. a first sortation of caseunits) and then removed from the respective multilevel verticalconveyors 150B in a second predetermined sequence (e.g. a secondsortation of case units) so that the case units may be placed on palletsor other suitable shipping containers/devices) in a predetermined order.For example, in the first sortation of case units the bots 110 may pickrespective case units (e.g. case unit) in any order. The bots 110 maytraverse the picking aisles and transfer deck (e.g. circulate around thetransfer deck) with the picked item until a predetermined time when theitem is to be delivered to a predetermined multilevel vertical conveyor150B. In the second sortation of case units, once the case units are onthe multilevel vertical conveyor 150B the case units may circulatearound the conveyor until a predetermined time when the item are to bedelivered to the out-feed transfer station 160. Referring to FIG. 21, itis noted that the order of case units delivered to the pallets maycorrespond to, for example, store plan rules 9000. The store plan rules9000 may incorporate, for example, an aisle layout in the customer'sstore or a family group of case units corresponding to, for example, aparticular location in the store where the pallet will be unloaded or atype of goods. The order of case units delivered to the pallets may alsocorrespond characteristics 9001 of the case units such as, for example,compatibility with other case units, dimensions, weight and a durabilityof the case units. For example, crushable case units may be delivered tothe pallet after heavier more durable case units are delivered to thepallet. The first and second sortations of the case units allows for thebuilding of mixed pallets 9002 as described below.

The control server 120 in combination with the structural/mechanicalarchitecture of the storage and retrieval system enables maximum loadbalancing. As described herein, the storage spaces/storage locations aredecoupled from the transport of the case units through the storage andretrieval system. For example, the storage volume (e.g. the distributionof case units in storage) is independent of and does not affectthroughput of the case units through the storage and retrieval system.The storage array space may be substantially uniformly distributed withrespect to output. The horizontal sortation (at each level) and highspeed bots 110 and the vertical sortation by the multilevel verticalconveyors 150B substantially creates a storage array space that issubstantially uniformly distributed relative to an output location fromthe storage array (e.g. an out-feed transfer station 160 of a multilevelvertical conveyor 150B). The substantially uniformly distributed storagespace array also allows case units to be output at a desiredsubstantially constant rate from each out-feed transfer station 160 suchthat the case units are provided in any desired order. To effect themaximum load balancing, the control architecture of the control server120 may be such that the control server 120 does not relate the storagespaces within the storage structure 130 (e.g. the storage array) to themultilevel vertical conveyors 150B based on a geographical location ofthe storage spaces (which would result in a virtual partitioning of thestorage spaces) relative to the multilevel vertical conveyors 150B (e.g.the closest storage spaces to the multilevel vertical conveyor are notallocated to cases moving from/to that multilevel vertical conveyor).Rather, the control server 120 may map the storage spaces uniformly toeach multilevel vertical conveyor 150B and then select bots 110, storagelocations and output multilevel vertical conveyor 150B shelf placementso that case units from any location in the storage structure come outfrom any desired multilevel vertical conveyor output (e.g. at theout-feed transfer stations) at a predetermined substantially constantrate in a desired order.

Referring also to FIG. 22, as an exemplary operation of an orderfulfillment process of the storage and retrieval system 100, case unitsfor replenishing the picking stock are input at, for example,depalletizing workstations 210 (FIG. 13) so that case units bundledtogether on pallets (or other suitable container-like transportsupports) are separated and individually carried on, for example,conveyors 240 (FIG. 13) or other suitable transfer mechanisms (e.g.manned or automated carts, etc.) to the in-feed transfer stations 170(FIG. 22, Block 2200). The in-feed transfer stations 170 load theindividual case units onto respective multilevel vertical conveyors150A, which carry the case units to a predetermined level of the storagestructure 130 (FIG. 22, Block 2210). Bots 110 located on thepredetermined level of the storage structure 130 interface with themultilevel vertical conveyor 150A for removing the individual case unitsfrom the multilevel vertical conveyor 150A and transporting the caseunits to predetermined storage areas within the storage structure 130.In alternate embodiments, the bots 110 assigned to the predeterminedlevel interface with the bot transfer stations 140 for transferring thecase units from the bot transfer stations 140 to a predetermined storagemodule of the storage structure 130. It is noted that each multilevelvertical conveyor 150A is capable of providing case units to any storagearea within the storage structure 130. For example, a shelf 730 (FIG.3A) of any one of the multilevel vertical conveyors 150A of the storageand retrieval system 100 may be moved to any one of the storage levelsof the storage structure 130 (FIG. 22, Block 2220). Any bot 110 on adesired storage level may pick one or more case units (e.g. a pickface)from the shelf 730 (FIG. 3A) of the multilevel vertical conveyor 150A(FIG. 22, Block 2230). The bot 110 may traverse the transfer deck 130B(FIGS. 1 and 13-15) for accessing any one of the picking aisles 130A ona respective level of the storage structure 130 (FIG. 22, Block 2240).In a desired one of the picking aisles the bot can access any one of thestorage areas of that picking aisle for placing the case units in anydesired storage area regardless of the position of the storage arearelative to the multilevel vertical conveyor 150A used to place the caseunits in the storage structure 130 (FIG. 22, Block 2250). Thus, anydesired multilevel vertical conveyor 150A is capable of providing casesto a storage space located anywhere in the storage and retrieval system,regardless of the storage level or placement of the storage area on thatlevel.

As may be realized case units of the same type may be stored indifferent locations within the storage structure 130 so that at leastone of that type of item may be retrieved when other ones of that typeof item are inaccessible. The storage and retrieval system may also beconfigured to provide multiple access paths or routes to each storagelocation (e.g. pickface) so that bots may reach each storage locationusing, for example, a secondary path if a primary path to the storagelocation is obstructed. It is noted that the control server 120 and oneor more sensors on the bots 110 may allow for the assignment andreservation of a pickface for putting away an inbound item such asduring replenishment of the storage and retrieval system 100. In oneexemplary embodiment, when a storage slot/space becomes available in thestorage structure 130, the control server 120 may assign a fictitiousitem (e.g. an empty case) to the empty storage slot. If there areadjacent empty slots in the storage structure the empty cases of theadjacent storage slots may be combined to fill the empty space on thestorage shelf. As may be realized, the size of the slots may be variablesuch as when dynamically allocating shelf space. For example, referringalso to FIGS. 20A-20C, instead of placing case units 5011 and 5012 inpredetermined storage areas on the storage shelf 5001, the storage slotsmay be dynamically allocated such that the cases 5011, 5012 are replacedby three cases having the size of case unit 5010. For example, FIG. 20Aillustrates a storage bay 5000 divided into storage slots S1-S4 as isdone in conventional storage systems. The size of the storage slotsS1-S4 may be a fixed size dependent on a size of the largest item (e.g.item 5011) to be stored on the shelf 600 of the storage bay 5000. As canbe seen in FIG. 20A, when case units 5010, 5012, 5013 of varyingdimensions, which are smaller than item 5011, are placed in a respectivestorage slot S1, S2, S4 a significant portion of the storage baycapacity, as indicated by the shaded boxes, remains unused. Inaccordance with an exemplary embodiment, FIG. 20B illustrates a storagebay 5001 having dimensions substantially similar to storage bay 5000. InFIG. 20B the case units 5010-5016 are placed on the shelf 600 usingdynamic allocation such that the empty storage slots are substantiallycontinuously resized as uncontained case units are placed on the storageshelves (e.g. the storage slots do not have a predetermined size and/orlocation on the storage shelves). As can be seen in FIG. 20B,dynamically allocating the storage space allows placement of case units5014-5016 on shelf 600 in addition to case units 5010-5013 (which arethe same case units placed in storage bay 5000 described above) suchthat the unused storage space, as indicated by the hatched boxes, isless than the unused storage space using the fixed slots of FIG. 20A.FIG. 20C illustrates a side by side comparison of the unused storagespace for the fixed slots and dynamic allocation storage describedabove. It is noted that the unused storage space of bay 5001 usingdynamic allocation may be decreased even further by decreasing theamount of space between the case units 5010-5016 which may allow forplacement of additional case units on the shelf 600. As may be realized,as case units are placed within the storage structure the open storagespaces may be analyzed, by for example the control server 120, aftereach item placement and dynamically re-allocated according to a changedsize of the open storage space so that additional case units having asize corresponding to (or less than) a size of the re-allocated storagespace may be placed in the re-allocated storage space. In alternateembodiments, the storage slots may also be allocated so that case unitsthat are frequently picked together are located next to each other. Whena predetermined pickface is reserved for an item that is beingdelivered, at least a portion of the empty case sitting in the locationwhere the item is to be placed is replaced by a fictitious item havingthe features (e.g. size, etc.) of the item being delivered to preventother inbound case units from being assigned to the predeterminedpickface. If the item, is smaller than the empty case that it isreplacing the empty case may be resized or replaced with a smaller emptycase to fill the unused portion of the storage shelf. Another item maythen be placed within the storage slot corresponding to the resizedsmaller empty case and so on.

When an order for individual case units is made any bots 110 on thestorage level of the requested case units retrieves the correspondingcase units from a designated storage area of the storage structure 130(FIG. 23, Block 2300). The bot 110 traverses the picking aisle 130A inwhich the case units were stored and the transfer aisle 130B foraccessing any desired shelf 730 (FIG. 3B) of any one of the multilevelvertical conveyors 150B (FIG. 23, Block 2310): It is noted that the caseunits that comprise the order may be picked by the bots in any order.For example, a first bot 110 may traverse, for example, the transferdeck 130B for any suitable amount of time to, for example, allow otherbots to pick respective case units of the order and deliver those caseunits to the multilevel vertical conveyor 150B if the case units of theother bots are to be delivered to the multilevel vertical conveyorbefore the case units of the first bot 110. As described herein, thecase units may be delivered to the multilevel vertical conveyor at apredetermined time according to, for example, a predetermined sequencein a first sortation of the case units (FIG. 23, Block 2320). The bot110 transfers the case units to the desired shelf of the multilevelvertical conveyor as described above (FIG. 23, Block 2330). In alternateembodiments, the bots may provide the case units to bot transferstations 140 located on a level of the storage structure 130 from whichthe ordered case units were picked. The multilevel vertical conveyor150B transports the individual ordered case units to the out-feedtransfer stations 160 at a predetermined time according to, for example,a predetermined sequence in a second sortation of the case units (FIG.23, Block 2340). It is noted that the multilevel vertical conveyors 150Bare configured to allow the case units to continuously revolve aroundthe conveyor loop so that the case units can be moved to, for example,an out-feed transfer station at any suitable time for fulfilling anorder. For example, a first case unit is placed on a first shelf of themultilevel vertical conveyor 150B and a second case unit is placed on asecond shelf of the multilevel vertical conveyor 150B where the firstshelf is located in front of the second shelf in a sequence of shelvesof the multilevel vertical conveyor 150B and the second case unit is tobe provided to the out-feed transfer station 160 before the first caseunit. The first shelf (holding the first case unit) may be allowed topass the out-feed transfer station without unloading the first case unitto allow the second case unit to be removed from the second shelf. Thus,the case units may be placed on the shelves of the multilevel verticalconveyor 150B in any order. The out-feed transfer station 160 removesthe case units from a desired shelf of the multilevel vertical conveyorat a desired time (FIG. 23, Block 2350) so that the individual caseunits are transported to palletizing workstations 220 (FIG. 13) byconveyors 230 (FIG. 13) where the individual case units are placed onoutbound pallets (or other suitable container-like transport supports)in, for example, a predetermined sequence (as described above) to formmixed pallets 9002 (FIG. 21) for shipping to a customer. The out-feedtransfer stations 160 and the palletizing workstations 220 may bereferred to collectively as an order assembly station. Other examples,of material handling systems in which case units are transferred to anoutbound container can be found in U.S. patent application Ser. No.10/928,289 filed on Aug. 28, 2004, and U.S. patent application Ser. No.12/002,309 filed on Dec. 14, 2007, the disclosures of which areincorporated by reference herein in their entirety. As may be realized,the storage and retrieval system described herein allows for orderingmixed case units of any suitable quantity without having to pick andtransport, for example, entire trays, totes or pallets of case units toand from the storage structure 130.

Referring now to FIGS. 13-15, exemplary configurations of the storageand retrieval system 100 are shown. As can be seen in FIG. 13, thestorage and retrieval system 200 is configured as a single-ended pickingstructure in which only one side of the system 200 has a transfersection or deck 130B. The single-ended picking structure may be used in,for example, a building or other structure having loading docks disposedonly on one side of the building. As can be seen in FIG. 13, thetransfer deck 130B and picking aisles 130A allow bots 110 to traverse anentirety of a level of the storage structure 130 on which that bot 110is located for transporting case units between any suitable storagelocations/picking aisles 130A and any suitable multilevel verticalconveyors 150A, 150B. In this exemplary embodiment, the storage andretrieval system 200 includes a first and second storage section 230A,230B located side by side so that the picking aisles of each section aresubstantially parallel with each other and facing the same direction(e.g. towards transfer deck 130B).

FIG. 14 illustrates a storage and retrieval system 300 having a doublesided picking structure for use in, for example, buildings or otherstructures having loading docks on two sides of the building. In FIG. 14the storage and retrieval system 300 includes two storage sections 340A,340B that are arranged so that the picking aisles 130A in each of thestorage sections 340A, 340B are parallel with each other but facingopposing directions such that substantially continuous picking aislesare formed between the opposing transfer decks 330A, 330B. As may berealized, an express travel lane 335 may be located between the opposingtransfer decks 330A, 330B for allowing bots 110 to transit between thetransfer decks 330A, 330B at greater speeds than those allowed withinthe picking aisles 130A. As may also be realized the bots 110 on eachlevel of the picking structure of FIG. 14 may traverse the entirety ofits respective level such that the bot 110 may serve to transport caseunits throughout the two storage sections 340A, 340B and to and fromrespective input and output workstations.

FIG. 15 illustrates a storage and retrieval system 400 substantiallysimilar to storage and retrieval system 300. However, the storage andretrieval system 400 illustrates maintenance access gateways 410A, 410B,410C for allowing, as an example, humans and/or service equipment toenter the storage and retrieval system for performing maintenance and/orrepairs to the storage and retrieval system 400. The storage andretrieval systems may also be configured with suitable features fordisabling one or more bots 110, conveyors or any other suitable featuresof the storage and retrieval systems in one or more areas of the storageand retrieval system 100 when maintenance is being performed within thestorage and retrieval system 100. In one example, the control server 120may be configured to disable/enable features of the storage andretrieval system.

The storage and retrieval systems, such as those described above withrespect to FIGS. 13-15 may be configured to allow substantiallyunimpeded access to substantially all areas of the storage and retrievalsystem in the event of, for example, a stoppage in the system so thatthe system continues operation with substantially no or minimized lossin throughput. A stoppage in the system may include, but is not limitedto, a disabled bot 110 within a picking aisle or on a transfer deck, adisabled multilevel vertical conveyor 150A, 150B and/or a disabledin-feed or out-feed transfer station 160, 170. As may be realized thestorage and retrieval system 200, 300, 400 may be configured to allowsubstantially redundant access to each of the storage locations withinthe picking aisles 130A. For example, a loss of an input multilevelvertical conveyor 150A may result in substantially no loss of storagespace or throughput as there are multiple input multilevel verticalconveyors 150A that can transport case units to each level/storage spacewithin the storage structure 130. As another example, the loss of a botout of a picking aisle may result in substantially no loss of storagespace or throughput as there are multiple bots 110 on each level capableof transferring case units between any one of the storage spaces and anyone of the multilevel vertical conveyors 150A, 150B. In still anotherexample, the loss of a bot 110 within a picking aisle may result insubstantially no loss of storage space or throughput as only a portionof a picking aisle is blocked and the storage and retrieval system maybe configured to provide multiple paths of travel to each of the storagespaces or types of case units within the storage spaces. In yet anotherexample, a loss of an output multilevel vertical conveyor 150B mayresult in substantially no loss of storage space or throughput as thereare multiple output multilevel vertical conveyors 150B that cantransport case units from each level/storage space within the storagestructure 130. In the exemplary embodiments, transport of the case units(e.g. via the multilevel vertical conveyors and bots) is substantiallyindependent of storage capacity and case unit distribution and viceversa (e.g. the storage capacity and case unit distribution issubstantially independent of transport of the case units) such thatthere is substantially no single point of failure in either storagecapacity or throughput of case units through the storage and retrievalsystem.

The control server 120 may be configured to communicate with the bots110, multilevel vertical conveyors 150A, 150B, in-feed or out-feedtransfer stations 160, 170 and other suitable features/components of thestorage and retrieval system in any suitable manner. The bots 110,multilevel vertical conveyors 150A, 150B and transfer stations 160, 170may each have respective controllers that communicate with the controlserver 120 for conveying and/or receiving, for example, a respectiveoperational status, location (in the case of the bots 110) or any othersuitable information. The control server may record the information sentby the bots 110, multilevel vertical conveyors 150A, 150B and transferstations 160, 170 for use in, for example, planning order fulfillment orreplenishment tasks.

As may be realized any suitable controller of the storage and retrievalsystem such as for example, control server 120, may be configured tocreate any suitable number of alternate pathways for retrieving one ormore case units from their respective storage locations when a pathwayproviding access to those case units is restricted or blocked. Forexample, the control server 120 may include suitable programming, memoryand other structure for analyzing the information sent by the bots 110,multilevel vertical conveyors 150A, 150B and transfer stations 160, 170for planning a bot's 110 primary or preferred route to a predetermineditem within the storage structure. The preferred route may be thefastest and/or most direct route that the bot 110 can take to retrievethe item. In alternate embodiments the preferred route may be anysuitable route. The control server 120 may also be configured to analyzethe information sent by the bots 110, multilevel vertical conveyors150A, 150B and transfer stations 160, 170 for determining if there areany obstructions along the preferred route. If there are obstructionsalong the preferred route the control server may determine one or moresecondary or alternate routes for retrieving the item so that theobstruction is avoided and the item can be retrieved without anysubstantial delay in, for example, fulfilling an order. It should berealized that the bot route planning may also occur on the bot 110itself by, for example, any suitable controller system, such as controlsystem 1220 (FIG. 1) onboard the bot 110. As an example, the bot controlsystem 1220 may be configured to communicate with the control server 120for accessing the information from other bots 110, the multilevelvertical conveyors 150A, 150B and the transfer stations 160, 170 fordetermining the preferred and/or alternate routes for accessing an itemin a manner substantially similar to that described above. It is notedthat the bot control system 1220 may include any suitable programming,memory and/or other structure to effect the determination of thepreferred and/or alternate routes.

Referring to FIG. 15 as a non-limiting example, in an order fulfillmentprocess the bot 110A, which is traversing transfer deck 330A, may beinstructed to retrieve an item 499 from picking aisle 131. However,there may be a disabled bot 110B blocking aisle 131 such that the bot110A cannot take a preferred (e.g. the most direct and/or fastest) pathto the item 499. In this example, the control server may instruct thebot 110A to traverse an alternate route such as through any unreservedpicking aisle (e.g. an aisle without a bot in it or an aisle that isotherwise unobstructed) so that the bot 110A can travel along transferdeck 330B. The bot 110A can enter the end of the picking aisle 131opposite the blockage from transfer deck 330B so as to avoid thedisabled bot 110B for accessing the item 499. In other exemplaryembodiment, as can be seen in FIG. 14, the storage and retrieval systemmay include one or more bypass aisles 132 that run substantiallytransverse to the picking aisles to allow the bots 110 to more betweenpicking aisles 130A in lieu of traversing the transfer decks 330A, 330B.The bypass aisles 132 may be substantially similar to travel lanes ofthe transfer decks 330A, 330B, as described herein, and may allowbidirectional or unidirectional travel of the bots through the bypassaisle. The bypass aisle may provide one or more lanes of bot travelwhere each lane has a floor and suitable guides for guiding the botalong the bypass aisle in a manner similar to that described herein withrespect to the transfer decks 330A, 330B. In alternate embodiments, thebypass aisles may have any suitable configuration for allowing the bots110 to traverse between the picking aisles 130A. It is noted that whilethe bypass aisle 132 is shown with respect to a storage and retrievalsystem having transfer decks 330A, 330B disposed on opposite ends of thestorage structure, in other exemplary embodiments storage and retrievalsystems having only one transfer deck, such as shown in FIG. 13, mayalso include one or more bypass aisles 132. As may also be realized, ifone of the in-feed or out-feed transfer stations 160, 170 becomedisabled order fulfillment or replenishment tasks may be directed, byfor example control server 120, to other ones of the in-feed andout-feed transfer stations 160, 170 without substantial disruption ofthe storage and retrieval system.

The storage and retrieval systems shown in FIGS. 1 and 13-15 haveexemplary configurations only and in alternate embodiments the storageand retrieval systems may have any suitable configuration and componentsfor storing and retrieving case units as described herein. For example,in alternate embodiments the storage and retrieval system may have anysuitable number of storage sections, any suitable number of transferdecks and corresponding input and output workstations. As an example, astorage and retrieval system in accordance with the exemplaryembodiments may include transfer decks and corresponding input andoutput stations located on three or four sides of the storage sectionsfor serving, for example, loading docks disposed on various sides of abuilding.

Referring also to FIGS. 16, 17A and 17B, the storage structure 130 willbe described in greater detail. In accordance with an exemplaryembodiment, the storage structure 130 includes, for example, anysuitable number of vertical supports 612 and any suitable number ofhorizontal supports 610, 611, 613. It is noted that the terms verticaland horizontal are used for exemplary purposes only and that thesupports of the storage structure 130 may have any suitable spatialorientation. In this exemplary embodiment, the vertical supports 612 andhorizontal supports 610, 611, 613 may form an array of storage modules501, 502, 503 having storage bays 510, 511. The horizontal supports 610,611, 613 may be configured to support the storage shelves 600 (describedbelow) as well as the floors 130F for the isle spaces 130A, which mayinclude tracks for the bots 110. The horizontal supports 610, 611, 613may be configured to minimize the number of splices between horizontalsupports 610, 611, 613 and thus, the number of splices that, forexample, tires of the bots 110 will encounter. For exemplary purposesonly, the aisle floor 130F may be a solid floor constructed of plymetalpanels having, for example, a wood core sandwiched between sheets ofsheet metal. In alternate embodiments the floors 130F may have anysuitable layered, laminated, solid or other construction and beconstructed of any suitable material(s), including, but not limited toplastics, metals, woods and composites. In yet other alternateembodiments the aisle floors 130F may be constructed of a honeycombstructure or other suitable lightweight yet substantially rigidstructure. The aisle floors 130F may be coated or treated with wearresistant materials or include replaceable sheets or panels that may bereplaced when worn. Tracks 1300 (FIG. 15) for the bots 110 may beincorporated into or otherwise affixed to the aisle floors 130F forguiding the bots 110 in substantially straight lines or paths of travelwhile the bots 110 are traveling within the storage structure 130.Suitable examples of tracks 1300 are described in U.S. patentapplication Ser. No. 12/757,312, entitled “AUTONOMOUS TRANSPORTS FORSTORAGE AND RETRIEVAL SYSTEMS,”previously incorporated by reference. Thefloors 130F may be attached to, for example, one or more of the verticaland horizontal supports (or any other suitable support structure) in anysuitable manner such as with any suitable fasteners including, but notlimited to bolts and welds. In one exemplary embodiment, as can be seenin, for example, FIG. 8C, the tracks 1300 may be fixed to one or morevertical supports of the storage structure in any suitable manner suchthat the bot straddles adjacent tracks 1300 for traversing a pickingaisle. As can be seen in FIG. 8C one or more of the picking aisles maybe substantially vertically unobstructed by floors (e.g. the pickingaisles do not have floors). The absence of floors on each picking levelmay allow maintenance personnel to walk down the picking aisles wherethe height between each storage level would otherwise substantiallyprevent the maintenance personnel from traversing the picking aisles.

Each of the storage bays 510, 511 may hold the picking stock on storageshelves 600 that are separated by the picking aisles 130A. It is notedthat in one exemplary embodiment the vertical supports 612 and/orhorizontal supports 610, 611, 613 may be configured to allow foradjusting the height or elevation of the storage shelves and/or aislefloors 130F relative to, for example, each other and a floor of thefacility in which the storage and retrieval system is located. Inalternate embodiments the storage shelves and floors may be fixed inelevation. As can be seen in FIG. 16, storage module 501 is configuredas an end module having, for example, about half the width of the otherstorage modules 502, 503. As an example, the end module 501 may have awall located on one side and the picking aisle 130A located on theopposite side. The depth Dl of end module 501 may be such that access tothe storage shelves 600 on module 501 is achieved by the picking aisle130A located on but one side of the storage module 501, whereas thestorage shelves 600 of modules 502, 503 may be accessed by pickingaisles 130A located on both sides of the modules 502, 503 allowing for,as an example, the storage modules 502, 503 having a depth substantiallytwice that of the depth Dl of storage module 501.

The storage shelves 600 may include one or more support legs 620L1,620L2 extending from, for example, the horizontal supports 610, 611,613. The support legs 620L1, 620L2 may have any suitable configurationand may be part of, for example, a substantially U-shaped channel 620such that the legs are connected to each other through channel portion620B. The channel portion 620B may provide an attachment point betweenthe channel 620 and one or more horizontal supports 610, 611, 613. Inalternate embodiments, each support leg 620L1, 620L2 may be configuredto individually mount to the horizontal supports 610, 611, 613. In thisexemplary embodiment, each support leg 620L1, 620L2 includes a bentportion 620H1, 620H2 having a suitable surface area configured tosupport case units stored on the shelves 600. The bent portions 620H1,620H2 may be configured to substantially prevent deformation of the caseunits stored on the shelves. In alternate embodiments the leg portions620H1, 620H2 may have a suitable thickness or have any other suitableshape and/or configuration for supporting case units stored on theshelves. As can be seen in FIGS. 17A and 17B, the support legs 620L1,620L2 or channels 620 may form a slatted or corrugated shelf structurewhere spaces 620S between, for example, the support legs 620L1, 620L2allow for arms or fingers of the bots 110 to reach into the shelving fortransferring case units to and from the shelves. It is noted that thesupport legs 620L1, 620L2 of the shelves 600 may be configured forstoring case units, where adjacent case units are spaced any suitabledistance from each other. For example, a pitch or spacing between thesupport legs 620L1, 620L2 in the direction of arrow 698 may be such thatthe case units are placed on the shelves 600 with a distance of aboutone pitch between the case units to, for example, minimize contactbetween case units as the case units are placed and removed from theshelves by the bots 110. For exemplary purposes only, case units locatedadjacent one another may be spaced apart, for example, in direction 698a distance of about 2.54 cm. In alternate embodiments the spacingbetween the case units on the shelves may be any suitable spacing. It isalso noted that transfer of case units to and from the multilevelvertical conveyors 150A, 150B (whether the transfer is made directly orindirectly by the bot 110) may occur in a substantially similar mannerto that described above with respect to the storage shelves 600.

Referring again to FIGS. 13-15, at the end of each aisle in the storagestructure 130 there may be a transition bay 290 (FIG. 13) that allowsthe bots 110 to transition onto the transfer decks 130B. As describedabove, the transfer decks 130 may be located at one or more ends of theaisles 130A. In one example, the transition bay 290 may be configured toallow the bots 110 to transition from travel along a rail(s) within theaisles 130A to travel that is free from being constrained by railswithin the transfer decks 130B and to merge with bot traffic on thetransfer decks 130B. The transfer decks 130B may include a stacked orvertical array of, for example, substantially looped decks, where eachlevel of the storage structure 130 includes one or more respectivetransfer decks 130. In alternate embodiments the transfer decks may haveany suitable shape and configuration. The transfer decks 130B may beunidirectional decks (i.e. bots 110 travel in a single predetermineddirection around the transfer deck 130B) configured to connect all ofthe picking aisles 130A on a respective level to corresponding input andoutput multilevel vertical conveyors 150A, 150B on the respective level.In alternate embodiments the transfer decks may be bidirectional forallowing the bots to travel in substantially opposite directions aroundthe transfer decks. To allow the bots 110 to access the multilevelvertical conveyors 150A, 150B without obstructing the travel lanes ofthe transfer decks 130B, each transfer deck 130B may be configured withspurs or transfer areas 295 which may extend from the transfer decks130B. In one exemplary embodiment the transfer areas 295 may includetracks substantially similar to tracks 1300 (FIG. 15) for guiding thebots 110 to the multilevel vertical conveyors 150A, 150B and/or bottransfer stations 140. In alternate embodiments, the bots may travel andbe guided within the spurs 295 in a manner substantially similar to thatdescribed herein with respect to the transfer decks.

The travel lanes of the transfer decks 130B may be wider than the travellanes within the aisles of the storage structure 130. For exemplarypurposes only, travel lanes of the transfer decks 130B may be configuredto allow the bots 110 to make different types of turns when, forexample, transitioning onto or off of the transfer decks 130B. Thedifferent types of turns may correspond to a desired orientation of thebot 110 within the picking aisles 130A or a lane of the transfer deck130B on which the bot 110 is travelling. For exemplary purposes only,referring to FIGS. 18-19B, generally, on the transfer deck 130B, the bot110 uses casters 1261, 1262 (or releases lockable casters 1260′, 1261′)while making substantially right angle turns when transitioning from/tothe picking aisles 130A or transfer areas 295. For traveling longdistances on, for example, the transfer deck 130B the bot 110 travels onwheels 1211-1214 (or lockable casters 1260′, 1261′ in lieu of idlerwheels 1213, 1214 where the casters 1260′, 1261′ are rotationally lockedas described above) using a “skid steering” algorithm (e.g. slowing downor stopping rotation of one drive wheel relative to the other drivewheel to induce a turning motion on the bot) to follow guidance lines1813-1817 on the transfer deck 130B.

When traveling in the picking aisles 130A, the bot 110 travels insubstantially straight lines. These substantially straight line moveswithin the picking aisles 130A can be in either direction 1860, 1861 andwith either bot orientation (e.g. a forward orientation with the driveend 1298 trailing the direction of travel and a reverse orientation withthe drive end 1298 leading the direction of travel). During straightline motion on the transfer deck 130B the bot 110 travels in, forexemplary purposes only, a counterclockwise direction 1863, with aforward bot orientation. In alternate embodiments the bot may travel inany suitable direction with any suitable bot orientation. In still otheralternate embodiments, there may be multiple travel lanes allowing botsto travel in multiple directions (e.g. one travel lane has a clockwisedirection of travel and another travel lane has a counter-clockwisedirection of travel). In one example, the turns to and from the pickingaisles 130A and/or transfer areas 295 are about 90 degrees where thecenter point of rotation P of the bot is located substantially midwaybetween the drive wheels 1211, 1212 such that the bot can rotateclockwise or counterclockwise. In alternate embodiments the bot turnsmay be more or less than about 90 degrees. In another example, the botmay make a substantially 180 degree turn (i.e. two substantially 90degree turns made in sequence without a stop).

As described above, the transfer deck 130B may include guidance lines1810-1817 for guiding the bot 110. The guidance lines 1810-1817 may beany suitable lines adhered to, formed in or otherwise affixed to thetransfer deck 130B. For exemplary purposes only, in one example theguidance lines may be a tape affixed to the surface of the transfer deck130B. In this exemplary embodiment the, transfer deck 130B includes atrack 1800 having a first side 1800A and a second side 1800B separatedby a wall 1801. The first and second sides 1800A, 1800B of the track1800 are joined by end track sections 1800E (only one of which is shownin FIG. 8). In alternate embodiments the track 1800 may have anysuitable configuration. Each of the first and second sides 1800A, 1800Bincludes two travel lanes defined by, for example, guidance lines 1813,1814 and 1816, 1817 respectively. The end track portions 1800E include,for example, one travel lane defined by, for example, guidance line1815. In alternate embodiments the sections/sides of the track 1800 mayhave any suitable number of travel lanes defined in any suitable manner.In accordance with the exemplary embodiments each picking aisle 130Aand/or transfer station, such as transfer station 140B (FIG. 1),includes a lead in/out guidance line 1810-1812. The lead in/out guidancelines 1810-1812 and the single guidance line 1815 of the end trackportions 1800E may be detected by the bot 110 as index marks for botlocalization during long line-following moves. The lead in/out guidancelines 1810-1812 and guidance line 1815 may also be detected by the bot110 as reference marks for making turns.

When the bot 110 moves in substantially straight lines, such as in thepicking aisles 130A and/or transfer areas 295, the drives for motors1211M, 1212M may be configured as torque controllers as described ingreater detail in U.S. patent application Ser. No. 12/757,312, entitled“AUTONOMOUS TRANSPORTS FOR STORAGE AND RETRIEVAL SYSTEMS,”previouslyincorporated by reference in its entirety. When travelling longdistances on, for example, the transfer deck, the bot 110 travels ondrive wheels 1211, 1212 and idler wheels 1213, 1214 (or locked casters1260′, 1261′) so that the bot is deterred from veering off of thestraight line trajectory through the fixed nature of the drive wheels1211, 1212 and idler wheels 1213, 1214 (or locked casters 1260′, 1261′).The computer 1701 may be configured with any suitable line followingalgorithm to substantially ensure that the bot 110 maintains travel in astraight line. The line following algorithm may also allow forcorrection of initial line following errors due to, for example,misalignment from turns. In one exemplary embodiment the bot 110 usesline sensors 1712 to estimate its heading and offset from a guidanceline 1810-1817. The bot 110 may be configured to use, for example, anysuitable algorithm such as a fuzzy logic algorithm to generatecorrections in the travel path of the bot 110. The correction may beapplied as a differential torque to the wheels as the bot is travelling(e.g. skid steering—rotating one drive wheel slower than the other drivewheel to produce increased drag on one side of the bot for inducing aturning moment on the bot).

For turns, such as for example, substantially right angle turns, thedrives for motors 1211M, 1212M may be configured as positioncontrollers. For example the drives may be commanded by the computer1701 to rotate their respective wheels in opposite directions for apredetermined distance to generate a pivot turn of slightly more thanabout 90 degrees. When for example, line sensors 1712 detect a stoppingguidance line, the turning move is terminated. In alternate embodimentsthe drives for the motors 1211M, 1212M may be operated in any suitablemanner for driving the bot in substantially straight lines or duringturns.

FIGS. 19A and 19B illustrate an exemplary turn sequence for asubstantially 90 degree turn made by the bot 110 while transitioningonto the transfer deck 130B from a picking aisle 130A. In this example,the bot is traveling in a forward orientation in the direction of arrow1910. As the bot 110 exits the picking aisle 130A, the bot 110 lowersthe casters 1260, 1261 (FIG. 4A) so that the idler wheels 1213, 1214 arelifted off of the transfer deck 130B (or unlocks casters 1260′, 1261′).Using line sensors 1712 located at for example the driven end 1299 ofthe bot 110, the bot 110 detects the inner travel lane guidance line1814 and then using corrected wheel odometry, stops with its pivot pointP at or close to the outer travel lane guidance line 1813. The bot 110rotates about 90 degrees in the direction of arrow 1920 using adifferential torque in the drive motors 1211M, 1212M to turn the drivewheels 1211, 1212 in opposite directions such that the bot 110 rotatesabout point P. The bot 110 detects the guidance line 1813 with the linesensors 1712 and terminates the turn. The bot 110 raises the casters1260, 1260 so that the idler wheels 1213, 1214 contact the transfer deck130B (or locks casters 1260′, 1261′) and proceeds to follow guidanceline 1813 using, for example, line following. It is noted that turningof the bot to enter, for example, picking aisle 130A may occur insubstantially the same manner as that described above for exiting thepicking aisle 130A. Other examples of turn sequences of the bot aredescribed in greater detail in U.S. patent application Ser. No.12/757,312, entitled “AUTONOMOUS TRANSPORTS FOR STORAGE AND RETRIEVALSYSTEMS,”previously incorporated by reference in its entirety.

Referring again to FIGS. 13-15, the floor 330F of the transfer decks mayhave any suitable construction configured to support the bots 110 asthey traverse their respective transfer deck(s) 130B. For exemplarypurposes only, the transfer deck floors 330F may be substantiallysimilar to the aisle floors 130F described above. In alternateembodiments the transfer deck floors 330F may have any suitableconfiguration and/or construction. The transfer deck floors 330F may besupported by a lattice of frames and columns that may be connected to,for example, one or more of the vertical supports 612 and horizontalsupports 610, 611, 613 in any suitable manner. For example, in oneexemplary embodiment the transfer decks may include cantilevered armsthat may be driven or otherwise inserted into corresponding slots,recesses or other openings in one or more of the vertical supports 612and horizontal supports 610, 611, 613. In alternate embodiments thetransfer deck floors 330F may be supported by a structure substantiallysimilar to that described above with respect to FIGS. 16, 17A and 17B.As may be realized, the pitch of the transfer deck floors 330F may besubstantially similar to the pitch of the respective aisle floors 130F.

In one exemplary embodiment, the storage structure 130 may includepersonnel floors 280 (which may include the maintenance access gateways410A-410C) associated with each level of the storage structure. Thepersonnel floors may be located, for example, within or adjacent to theaisles of the storage structure and/or the transfer decks 130B. Inalternate embodiments, the personnel floors 280 may be suitably locatedto provided reach in access to one side of the transfer decks 130B fromwithin the storage structure where the other opposite side of thetransfer decks 130B is accessed through work platforms/scaffoldingadjacent the workstations 210, 220 and/or multilevel vertical conveyors.In one exemplary embodiment, the personnel floors 280 may run the fulllength of each aisle 130A or transfer deck 130B. In alternateembodiments the personnel floors 280 may have any suitable length. Thepersonnel floors 280 may be vertically spaced from each other atpredetermined intervals where the space between the personnel floors 280provides a personnel work zone for resolving problems with, asnon-limiting examples, the bots 110, case units stored in the storagestructure 130 and the storage structure 130 itself. The personnel floors280 may be configured to provide walking surfaces for, as an example,maintenance technicians or other personnel where the walking zones aredistinct from travel lanes of the bots 110. Access to the personnelfloors may be provided through the maintenance access gateways 410A-410Cor any other suitable access point. Movable barriers or other suitablestructures may be provided along the aisles 130A and transfer decks 130Bto further separate unintentional interaction between, for example thebots 110 and personnel. In one exemplary embodiment, in normal operationthe movable barriers may be in a stowed or retracted position to allow,for example, the bot 110 to pass and access the storage shelves 600. Themovable barriers may be placed in an extended position when personnelare located in a predetermined zone or location of the storage structure130 to block bot 110 access to the aisle (s) or portions of the transferdecks where personnel are located. In one exemplary operation of storagestructure maintenance for a predetermined zone of the storage structure130, all active bots 110 may be removed from the predetermined zone.Bots 110 that require maintenance may be disabled and de-energizedwithin the predetermined zone. The movable barriers may be extended toprevent active bots 110 from entering the predetermined zone and anylocks preventing access to the personnel floors may be unlocked orremoved. The extension and retraction of the movable barriers, disablingof the bots 110 and removal of bots 110 from the predetermined zone maybe controlled in any suitable manner such as by, for example, anysuitable control system such as a central controller server 120 andmechanical and/or electromechanical interlocks. It is noted that inalternate embodiments, the storage and retrieval system may include anysuitable personnel access not limited to that described above.

The structure, such as structure 130, of the storage and retrievalsystems described herein may be configured to sustain predeterminedloads placed on the structure by normal service and events such as, forexemplary purposes only, earthquakes as defined by local and federalcodes. As an example, these loads may include the dead weight of thestructure, inventory stored in and transferred throughout the structure,the bots 110, seismic loads, thermal expansion and sufficient stiffnessfor bot control and positioning. The structure of the storage andretrieval systems 100 may also be configured for ease of assembly,maintenance access, modularity and efficient and economical materialuse. Non-limiting examples, of the codes to which the structure may beconfigured to comply include ASCE7, AISC Manual of Steel Construction,AISC Code of Standard Practice for Steel Buildings and Bridges, RMI(Rack Manufacturers Institute) and Materials Handling Industry ofAmerica. The structural components (e.g. vertical/horizontal supports,floors, etc.) of the storage and retrieval systems described herein mayalso include wear and/or corrosion resistant coatings including surfacetreatments such as, for example, paints and galvanization. In oneexample, the coating may include a base coating and a contrasting topcoating such that any wearing of the top coating will be readilyvisible. In alternate embodiments the coatings and surface treatmentsmay have any suitable configurations and colors so that wear is easilyidentifiable.

The storage structure 130 may be configured to be rapidly assembled andinstalled in the field in a “bottom up construction” (e.g. each level isconstructed sequentially such that lower levels in the sequence aresubstantially completed before the upper levels in the sequence). Forexample, the vertical supports 612 and/or horizontal supports 610, 611,613 (and/or any other components of the storage structure 130) may bepredrilled, punched or otherwise preformed with assembly holes. Baseplates for supporting each of the vertical supports 612 and for securingthe vertical supports 612 to a floor may be preinstalled on therespective vertical supports 612. Templates may be provided for locatinganchor bolts in the floor for securing the base plates. The verticalsupports 612 may be configured with brackets for receiving and at leastpartially securing the horizontal supports 610, 611, 613. Preformedholes in the horizontal supports may also be used to, for example, boltor otherwise fasten the horizontal supports to the vertical supports.The shelves 600 may be field assembled from prefinished components andaffixed to, for example, the horizontal supports 610, 611, 613 in anysuitable manner. Separate braces such as ties may be also provided forsecuring the horizontal supports 610, 611, 613. The transfer decks 130Bmay be installed in a manner substantially similar to that describedabove. The floors and decking of the storage structure 130 may beaffixed to the horizontal supports in any suitable manner, such as forexample through fasteners. The floors and decking may be preformed withinstallation holes to allow for securing the floors and decking to thehorizontal supports. The tracking 1300 (FIG. 15) for the bots 110 may bepreinstalled on or within the aisle flooring or installed in the fieldusing for example, preformed holes or other installation guides such astemplates. It is noted that in alternate embodiments, the storagestructure 130 may be constructed and assembled in any suitable manner.

It should be understood that the exemplary embodiments described hereinmay be used individually or in any suitable combination thereof. Itshould also be understood that the foregoing description is onlyillustrative of the embodiments. Various alternatives and modificationscan be devised by those skilled in the art without departing from theembodiments. Accordingly, the present embodiments are intended toembrace all such alternatives, modifications and variances that fallwithin the scope of the appended claims.

What is claimed is:
 1. An automated case unit storage system forhandling case units that are adapted for being palletized for shippingto or from a storage facility, the automated case unit storage systemcomprising: a multilevel array of storage spaces arrayed on multiplelevels and in multiple rows at each level, each storage space of thearray being capable of holding an uncontained case unit therein; acontinuous loop vertical lift having a lift support configured forholding and lifting the uncontained case unit to the levels of thearray, the continuous loop vertical lift moving the lift supportsubstantially continuously at a substantially constant rate; and atransport cart with an effector capable of holding the uncontained caseunit thereon, the cart being movable through the array on at least oneof the levels to effect transfer of the uncontained case unit from thelift support to the storage spaces; wherein the continuous loop verticallift and transport cart are arranged so that the uncontained case on thelift support can be transferred by the transport cart with one pick toeach storage space on the at least one level of the array with thecontinuous loop vertical lift moving the lift support at thesubstantially constant rate.
 2. The automated case unit storage systemof claim 1, wherein the continuous vertical lift is a common lift toeach storage space on the at least one level.
 3. The automated case unitstorage system of claim 1, wherein the continuous vertical lift is acommon lift to each storage space of the array of storage spaces.
 4. Theautomated case unit storage system of claim 1, wherein the each storagespace has fixed structure that defines a seating surface contacting theuncontained case unit stored in the storage space.
 5. The automated caseunit storage system of claim 1, wherein the effector is integral to anddependent from structure of the at least one transport cart, theeffector defining case unit seating surface contacting the uncontainedcase unit being held by the effector.
 6. An automated case unit storagesystem for handling case units that are adapted for being palletized forshipping to or from a storage facility, the automated case unit storagesystem comprising: a multilevel array of storage spaces arrayed onmultiple levels and in multiple rows at each level, each storage spaceof the array being capable of holding an uncontained case unit therein;at least one continuous loop vertical lift having a lift supportconfigured for holding and lifting the uncontained case unit to thelevels of the array, the continuous loop vertical lift moving , the liftsupport substantially continuously at a substantially constant rate; anda transport cart with an effector capable of holding the uncontainedcase unit thereon, the cart being movable through the array on at leastone of the levels to effect transfer of the uncontained case unit from arespective one of the storage spaces to the at least one continuous loopvertical lift; wherein each storage space and transport cart arearranged so that the uncontained case in a respective storage space canbe transferred by the transport cart with one pick to each of the atleast one continuous loop vertical lift on the at least one level of thearray with the at least one continuous loop vertical lift moving thelift support at the substantially constant rate.
 7. The automated caseunit storage system of claim 6, wherein each storage space on the atleast one level is a common storage space to the at least one continuousvertical lift on the at least one level.
 8. The automated case unitstorage system of claim 6, wherein each storage space of the array ofstorage spaces is a storage space to the continuous vertical lift.